Left ventricular conduits to coronary arteries and methods for coronary bypass

ABSTRACT

Left ventricular conduits and related methods are disclosed for achieving bypass of a partially or completely occluded coronary artery. More broadly, conduits for allowing communication of bodily fluids from one portion of a patient&#39;s body to another and related methods are disclosed, including conduits for forming a blood flow path from a chamber of the heart to a vessel or from one vessel to another. In other embodiments, the conduits achieve a coronary artery bypass by allowing blood communication between the left ventricle and the coronary artery or between a proximal portion of the coronary artery and a distal portion of the coronary artery. The conduits may be placed completely through the heart wall or extend only partially therein. Conduits may take on a variety of configurations for allowing the control of blood flow therethrough, including curved or tapered shapes. The conduits may also follow a variety of paths, including direct transmyocardial communication between the left ventricle and the coronary artery, or through the myocardium and into the intrapericardial space and then into the coronary artery. The conduits may be implanted through a variety of methods, including minimally invasive techniques. Also disclosed are various preferred embodiments of medical devices and related methods for implanting the conduits including rigid delivery rods for penetrating bodily tissue. The delivery rods may be solid, thus being trocar-like, or hollow to form a self-implantable conduit. Other preferred rod embodiments may have the conduits mounted thereon and take the form of a stylet or the like. The conduits may be one-piece, continuous conduits or made up of a number of plural sections joined together. Disclosures of various anastomosis devices are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/099,691, filed Sep. 10, 1998, U.S. ProvisionalApplication No. 60/099,720, filed Sep. 10, 1998, U.S. ProvisionalApplication 60/104,397, filed Oct. 15, 1998, and U.S. ProvisionalApplication 60/099,767 filed Sep. 19, 1998, and is acontinuation-in-part of application Ser. No. 09/016,485, filed Jan. 30,1998, and International Application No. PCT/US99/03483, filed Feb. 17,1999, all of which are hereby incorporated by reference herein in theirentirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to an apparatus and method for implantinga conduit to allow communication of fluids from one portion of apatient's body to another; and, more particularly, to a blood flowconduit to allow communication from a heart chamber to a vessel or viceversa, and/or vessel to vessel. Even more particularly, the inventionrelates to a left ventricular conduit and related conduit configurationsfor controlling the flow of blood through the conduit to achieve bypassof an occluded coronary artery.

[0004] 2. Description of Related Art

[0005] Coronary artery disease is a major problem in the U.S. andthroughout the world. In fact, about 1.1 million “open heart” proceduresare performed each year, and current estimates are that approximately4.8 million people suffer from some degree of congestive heart failure.

[0006] When coronary arteries or other blood vessels become clogged withplaque, the results are at the very least impairment of the efficiencyof the heart's pumping action. On the more severe side of the scale areheart attack and death. In some cases, clogged arteries can be unblockedthrough minimally invasive techniques such as balloon angioplasty. Inmore difficult cases, a surgical bypass of the blocked vessel isnecessary.

[0007] In a bypass operation, one or more arterial or venous segmentsare harvested from the body and then surgically inserted between theaorta and the coronary artery. The inserted vessel segments, ortransplants, act as a bypass of the blocked portion of the coronaryartery and thus provide for a free or unobstructed flow of blood to theheart. More than 500,000 bypass procedures are performed in the U.S.every year.

[0008] Coronary artery bypass grafting (CABG) has been used for morethan 30 years. Initially, the saphenous vein (SV) served as theprincipal conduit for coronary bypass, but studies over the last dozenyears have shown a 3540% increase in 10-year patency rate for theinternal thoracic artery (ITA) compared with the SV. The SV, in fact,has only been shown to have a 10-year patency rate of 50%. Since the mid1980's, not only the ITA, but also the alternative arterial conduitshave been increasingly used. These conduits include the grastroepiploicartery (GEA), inferior epigastric artery (IEA), and radial artery (RA),which have been used primarily as supplements to both the right and leftITA.

[0009] Although the use of arterial conduits results in demonstrablybetter long-term patency, use of arteries in place of the SV oftenrequires complex technical challenges, such as free grafts, sequentialanastomosis, and conduit-to-conduit anastomosis. Some of the reasons forthe difficulty in using arterial conduits reside in the fact that theyare much more fragile than the SV and therefore easier to damage, anddue to their smaller size, easier to occlude completely or partiallythrough technical error during grafting.

[0010] Such coronary artery bypass surgery, however, is a very intrusiveprocedure that is expensive, time-consuming and traumatic to thepatient. The operation requires an incision through the patient'ssternum (sternotomy), and the patient be placed on a bypass pump so thatthe heart can be operated on while not beating. A vein graft isharvested from the patient's leg, another highly invasive procedure, anda delicate surgical procedure is required to piece the bypass graft tothe coronary artery (anastomosis). Hospital stays subsequent to thesurgery and convalescence periods are prolonged.

[0011] As mentioned above, another conventional treatment ispercutaneous transluminal coronary angioplasty (PTCA) or other types ofangioplasty. However, such vascular treatments are not always indicateddue to the type or location of the blockage, or due to the risk of theemboli formation.

[0012] One bypass technique employed in the prior art is taught by Wilk(U.S. Pat. Nos. 5,287,861, 5,409,019, 5,662,124, and 5,429,144, theentirety of each of which is hereby incorporated herein by thisreference). These Wilk references teach the use of a stent which isintroduced through the myocardial wall from an adjacent coronary arteryto provide a bypass conduit between the left ventricle and the adjacentcoronary artery. In one embodiment, this technique teaches the deliveryof a transmyocardial bypass shunt in a collapsed, reduced-profileconfiguration, which requires radial expansion subsequent to delivery ina bore pre-formed in the myocardial wall. The bore is formed, forexample, by a drill, needle, Seldinger wire, dilating wires orcatheters, or other devices prior to stent placement and expansion.

[0013] In another embodiment, Wilk discloses the disposition of a stentin the myocardium so that the stent extends only in the myocardium. Thestent may extend only partially through the myocardium, from the leftventricle of the heart or from a coronary artery, upstream of a vascularobstruction. Alternatively, the stent may extend completely through themyocardium to establish a blood flow path or conduit from the leftventricle to a coronary artery, downstream of a vascular obstruction.

[0014] Where stents are used in the Wilk cardiac revascularizationtechniques to guide blood from the left ventricle, the stents may bedesigned to lock upon opening from collapsed insertion configurations.Such stents enable the infusion of blood into the myocardium duringsystole. The stents may be provided with one-way valves to regulate orcontrol the backflow of blood during diastole.

[0015] Thus, there is a continuing need for improved bypass methods andapparatus that allow for the realization of increased long-term patencyrates, and that are less physically traumatic to the patient.

SUMMARY OF THE INVENTION

[0016] Thus, in one preferred embodiment there is provided a newapparatus and method for performing a coronary artery by-pass operationwhich is less invasive and less traumatic to the patient thanconventional by-pass surgery. Another advantage of this embodiment isthat it requires no incision through the chest wall. In anotherembodiment there is provided a catheter assembly for use in performingthe method of the invention.

[0017] Conduit Utilizing Intrapericardial Space

[0018] In another embodiment, there is provided methodology and relatedmedical devices for effectively bypassing a blocked or partially blockedcoronary artery and providing oxygenated blood to the myocardium. Inaccordance with this embodiment, a coronary artery bypass methodutilizes a fluid communication conduit or shunt member. An upstream endportion of the shunt member is disposed in the myocardium of a patient'sheart so that the upstream end portion communicates with the leftventricle of the patient's heart. An opposite downstream end portion ofthe shunt member is placed in communication with a coronary artery ofthe patient downstream of a blockage in the coronary artery, so that anintermediate or middle portion of the shunt member is disposed in anintrapericardial space of the patient, outside of the myocardium andoutside of the coronary artery. The downstream end portion of the shuntis inserted into the coronary artery or, alternatively, attached to agenerally anterior wall of the coronary artery.

[0019] Where the downstream end portion of the shunt is attached to theanterior wall of the coronary artery, the method further comprisesforming an aperture in the anterior wall of the coronary artery afterattaching the downstream end portion of the shunt member to the anteriorwall, thereby opening communication between the shunt member and thecoronary artery. The shunt member is preferably deliveredintravascularly into the left ventricle of the patient's heart. Thedownstream end portion of the shunt member is then passed completelythrough the myocardium and the intrapericardial space to the anteriorwall of the coronary artery. The aperture in the coronary artery isformed by inserting a free end portion of an incising instrumentintravascularly and through the shunt member after disposition of theupstream end portion of the shunt member in the myocardium and afterattaching of the downstream end portion of the shunt member to thecoronary artery. The incising instrument is operated, after insertingthereof, to perforate the anterior wall of the coronary artery.

[0020] The incising instrument may be a laser instrument including anoptical fiber. The incising instrument is operated in part bytransmitting monochromatic or laser radiation through the optical fiberto the anterior wall of the coronary artery.

[0021] The method utilizing the shunt member further comprises forming apassageway through the myocardium prior to the disposing of the upstreamend portion of the shunt member in the myocardium. The passageway isformed by inserting a surgical instrument intravascularly into the leftventricle of the patient and operating the instrument from outside thepatient to bore or tunnel through the myocardium. The upstream endportion of the shunt member is disposed in the passageway andsubsequently the downstream end portion of the shunt member is placed incommunication with the coronary artery of the patient.

[0022] The shunt member may be deployed in a pericardioscopic operationwherein pericardioscopic surgical instruments are operated from outsidethe patient to manipulate the downstream end portion of the shunt memberand to place the downstream end portion of the shunt member intocommunication with the coronary artery of the patient after passing ofthe downstream end portion of the shunt member through the passageway inthe myocardium.

[0023] Where the downstream end portion of the shunt member is insertedinto the coronary artery, the sequence of operations is similar to thecase where the shunt member is attached to the anterior wall of thecoronary artery. The shunt member is delivered intravascularly into theleft ventricle of the patient's heart and subsequently the downstreamend portion of the shunt member is passed through the myocardium; thedownstream end portion of the shunt member is then inserted into thecoronary artery. In this case, as well, the shunt member may be deployedin a pericardioscopic operation wherein pericardioscopic surgicalinstruments are operated from outside the patient to place thedownstream end portion of the shunt member in communication with thecoronary artery.

[0024] Generally, in the above-described procedure, the downstream endportion of the shunt member communicates with the coronary arterydownstream of a blockage. During systole, blood travels from thepatient's left ventricle through the shunt member to the coronary arteryand then to the myocardium along natural vessels. It may be necessary,in some patients, to provide two or more shunt members, depending on thenumber of blockages and their locations along the coronary artery.

[0025] Conduit Construction

[0026] The shunt or conduit member comprises a generally tubular,rounded or circumferential member having a length greater than a widthof the myocardium. The shunt member is made of a biocompatible materialsuch as polyethylene or GORTEX™ and is flexible at least along themiddle or intermediate portion thereof. Accordingly, the intermediate ormiddle portion of the shunt member may be bent into an arc to facilitatethe formation of a proper junction between the downstream end portion ofthe shunt member and the coronary artery of the patient. The tubularshunt member may be provided with a one-way valve preventing back flowof blood from the coronary artery into the ventricle. In a specificembodiment of the invention, the upstream end portion of the tubularshunt member is wider than the downstream end portion.

[0027] As discussed above, an upstream end portion of a generallytubular shunt member may be disposed in a myocardium of a patient'sheart so that the upstream end portion communicates with a leftventricle of the patient's heart, while a downstream end portion of theshunt member is inserted into a coronary artery of the patientdownstream of a blockage in the coronary artery so that the downstreamend portion is disposed inside the coronary artery. In a variation ofthe present invention, the shunt member is deployed so as to be disposedonly inside the myocardium and the coronary artery. In contrast to theabove-described methodology, no portion of the shunt member lies in theintrapericardial space. In this variation of the method, the shuntmember is again delivered intravascularly into the left ventricle of thepatient's heart, with the downstream end portion being passed throughthe myocardium. However, in this variation, the downstream end portionis inserted directly into the coronary artery through a posterior wallthereof in contact with the myocardium.

[0028] Posterior Wall Access

[0029] A method for performing a myocardial revascularization comprises,in accordance with another embodiment of the present invention, forminga passageway at least partially through a myocardium of a patient froman outer surface of the patient's heart, and performing a surgicaloperation at an outer end of the passageway to permanently close thepassageway at the outer end. In a particular implementation of thisembodiment of the invention, the passageway includes a portion extendingthough a posterior wall of a coronary artery and is produced by formingan aperture in an anterior wall of the coronary artery and forming thepassageway in substantial alignment with the aperture. In this case, theclosure of the passageway is effectuated particularly by closing theaperture in the anterior wall of the coronary artery. The closing of theaperture in the anterior wall of the coronary artery may be effectuatedby one or more of several techniques, including suturing, plugging, andlaser coagulation. To reinforce the closure of the artery wall, a bracemay be placed over the closure. The brace may take the form of abiocompatible patch attached to the heart via suturing or laser welding.

[0030] Conduit Configurations

[0031] Pursuant to another feature of a myocardial revascularizationtechnique, in accordance with yet another embodiment of the presentinvention, a stent is inserted into the passageway formed at leastpartially through the patient's myocardium. The inserting of the stentis preferably performed prior to the performing of the surgicaloperation to close the passageway at the outer end. The myocardialrevascularization technique, including the insertion of the stent, maybe performed in open heart surgery or in a pericardioscopic operation.In either case, the aperture in the anterior wall of the coronary arteryand the passageway in the myocardium are formed by operating aninstrument taken from the group consisting of a surgical drill and asurgical laser.

[0032] The passageway formed to communicate at an inner end with a leftventricle of the patient may communicate at an outer end with a coronaryartery or, alternatively, may terminate in the myocardium after closureof the outer end of the passageway. In the former case, blood flows fromthe left ventricle through the passageway, the coronary artery and bloodvessels communicating with the coronary artery. In the latter case, themyocardium is revascularized directly by the passageway, rater thanindirectly through the coronary artery and its tributaries.

[0033] In a myocardial revascularization technique in accordance withanother embodiment of the present invention, the passageway may be oneof a plurality of similarly formed passageways extending from thecoronary artery into the myocardium of the patient. Each passageway isproduced by forming a plurality of openings in the anterior wall of thecoronary artery and forming the passageways in alignment with respectiveones of the openings. The passageways are effectively closed from theexternal environment (the intrapericardial space) by closing theopenings in the anterior wall of the coronary artery. Where a myocardialpassageway formed in accordance with this embodiment does not extendthrough or into a coronary artery, the closure of the passageway iseffectuated on an epicardium of the patient.

[0034] A stent for a coronary artery bypass or myocardiumrevascularization procedure in accordance with another embodiment of thepresent invention has a collapsed configuration and an expandedconfiguration. The expanded configuration may have an arcuate form, toprovide a curved flow path for blood upon implantation of the stent intoa myocardium of a patient. This curved flow path smoothly redirectsblood flow and minimizes possible adverse effects that the impulsiveforce of the blood might have on the patient's coronary artery and otherlayers of heart tissue. The stent may have a one-way valve forpreventing retrograde flow of blood.

[0035] Another stent in accordance with another embodiment has acollapsed configuration and an expanded configuration and is providedwith a sensor and means for transmitting signals from the sensor to areceiver external to the stent. The sensor is taken from the groupconsisting of a pressure sensor and a flow sensor.

[0036] Self-Inserting Conduits

[0037] In yet another embodiment of the present bypass apparatus thereis provided a self-inserting conduit for diverting blood directly fromthe left ventricle of the heart to the coronary artery at a point distalto the blockage, therefore bypassing the blocked portion of the vessel.The shunt comprises a stent in the form of a single conduit having anopening at either end, and adapted to be positioned in the myocardium.The coronary artery, the myocardium and the wall of the left ventricleof the heart are pierced by the conduit from an outside space or tissuein a transverse manner to provide a channel completely through from thecoronary artery to the left ventricle of the heart. An opening locatedon the distal end of the conduit is positioned in the coronary artery.Oxygenated blood is pumped from the left ventricle, through the distalopening, through the hollow central portion of the conduit, out of theproximal opening and into the coronary artery distal to the blockage.The conduit is anchored in the myocardium to provide a permanent passagefor blood to flow between the left ventricle of the heart and thecoronary artery, distal to the blockage.

[0038] The apparatus of the present invention is preferably implanted ina minimally invasive manner using thoroscopy or another endoscopicprocedure, although open surgery or other means of vascular access arealso possible.

[0039] Coronary Bypass

[0040] The present system preferably utilizes a combination conduitcomprising an access and shunt device for forming a diversion of theblood from the coronary and proximally to the stenosis. A similar accessand shunt device is located in the vessel distal of the stenosis toreceive the diverted blood and allow it to continue on its coursedownstream. The combination access/shunt device comprises a conduitelement for providing access to the vessel and anchoring the system inplace. The conduit pierces the artery from the outside and travelscompletely through it and into the myocardium or other heart tissueadjacent the coronary artery. The conduit has a conduit or barb orseries of barbs on its distal end and is otherwise designed so that ithas substantial resistance to pull back or exit from the vessel. Asnoted, the conduit pierces through the vessel from an outside space ortissue in a transverse manner. Mounted on top of the conduit is a shuntdevice which comprises an aperture and a diversion conduit. With theconduit in its anchoring position, the shunt device is located partiallyin the vessel and partially outside of the vessel from the direction inwhich the conduit entered. The aperture resides in the vessel to allowblood to enter therein and from there to the diversion tube which is influid communication with the aperture. This provides the shunt of bloodinto the diversion tube of the combination access/shunt device. Mountedon top of the diversion tube is a connector piece which mates with abypass conduit. These elements are also in fluid communication to allowthe blood to bypass the blockage and to be shunted to a location distalthereof.

[0041] At such distal location, another similar combination access/shuntdevice is placed to allow the shunted blood to re-enter the artery in afree-graft configuration, and continue on its path downstream. However,a single device can be used distal of the restriction and connected toan appropriate graft for revascularization.

[0042] The apparatus of the present invention is preferably implanted ina minimally invasive manner using thoroscopy or other endoscopicprocedure, although open surgery or other means of vascular access arealso possible. The apparatus can be implanted permanently, or can beused temporarily to provide a bypass system during various surgicalprocedures, including coronary bypass procedures.

[0043] Thus, the present system is used to direct the flow of bloodaround the blocked portion of the vessel. In one embodiment, a shunt isused to direct blood directly from the left ventricle of the heart tothe coronary artery at a point distal to the blockage. According to oneaspect of the invention, the shunt comprises a rigid, generallyelongated stent in the form of a single conduit having an opening ateither end, and adapted to be positioned in the myocardium. The coronaryartery, the myocardium and the wall of the left ventricle of the heartare pierced by the conduit from an outside space or tissue in atransverse manner to provide a channel completely through from thecoronary artery to the left ventricle of the heart. An opening locatedon the distal end of the conduit is positioned within the leftventricle. An opening on the proximal end of the conduit is positionedin the coronary artery. Oxygenated blood is pumped from the leftventricle, through the distal opening, through the hollow centralportion of the conduit, out of the proximal opening and into thecoronary artery distal to the blockage. The conduit is anchored in themyocardium to provide a permanent passage for blood to flow between theleft ventricle of the heart and the coronary artery, distal to theblockage.

[0044] Alternatively, the conduit can be used temporarily to maintainblood flow through the coronary artery during therapeutic procedures,such as coronary bypass. The conduit can be used to deliver a veingraft, and to provide for the passage of blood around the blockage untilthe anastomosis of the graft is complete.

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIGS. 1A-1E are schematic cross-sectional views of a human heart,showing successive steps in a transmyocardial coronary artery bypassoperation in accordance with one conduit embodiment of the presentinvention.

[0046]FIG. 2 is a schematic cross-sectional view of a human heartshowing an alternative conduit to that used in the operation of FIGS.1A-1E.

[0047]FIG. 3 is a schematic partial cross-sectional view, on a largerscale, showing a modification of the coronary artery bypass produced bythe operation of FIGS. 1A-1E.

[0048]FIG. 4 is a schematic cross-sectional view of a human heartshowing a modification of the coronary artery bypass operation depictedin FIGS. 1A-1E.

[0049]FIG. 5 is a schematic partial cross-sectional view, on a largerscale, showing a variation of the coronary artery bypass of FIG. 4.

[0050]FIG. 5A is a schematic view of a human heart showing a two piececonduit connecting the left ventricle to the left anterior descendingcoronary artery.

[0051]FIG. 5B is an enlarged view of the two piece conduit of FIG. 5A.

[0052]FIG. 5C is a schematic cross-sectional view of the two piececonduit of FIG. 5B.

[0053]FIG. 6A is a schematic partial cross-sectional view of anothercoronary artery bypass showing a conduit or shunt with a one-way valveopened during systole.

[0054]FIG. 6B is a schematic partial cross-sectional view similar toFIG. 6A, illustrating the shunt of FIG. 6A with the valve closed duringdiastole.

[0055] FIGS. 6C-6H are perspective views of conduits or stents withopenings into the coronary artery having hoods, valves, or other flowdirection/flow control devices.

[0056]FIG. 7 is a schematic cross-sectional view of a human heartshowing instrumentation used for implanting the shunt of FIGS. 6A and6B.

[0057]FIG. 8 is a schematic partial cross-sectional view of an arcuateconduit or stent with a one-way valve utilized in a further coronaryartery technique.

[0058] FIGS. 8A-8B are schematic partial cross-sectional views ofarcuate conduits or stents having narrow openings into the coronaryartery.

[0059] FIGS. 8C-8P are schematic partial cross-sectional views ofconduits or stents having a variety of configurations to achieve flowcontrol therethrough and to minimize backflow.

[0060]FIG. 9 is a block diagram of operational components with feedbackas to operational parameters.

[0061] FIGS. 9A-9B illustrate a conduit having a flow sensor formeasuring various blood flow parameters incorporated therein.

[0062]FIG. 9C is a schematic partial cross-sectional view of a conduithaving the flow sensor FIG. 9B as installed between two vessels.

[0063] FIGS. 10A-10C are schematic cross-sectional views of a humanheart, showing successive steps in a transmyocardial coronary arterybypass operation utilizing a penetrating rod for implanting a conduit.

[0064]FIG. 11 is a schematic cross-sectional view similar to FIG. 10C,showing three transmyocardial conduits or stents implanted pursuant tothe procedure of FIGS. 10A-10C.

[0065]FIG. 12 is a schematic partial cross-sectional view of anartificial myocardial revascularization showing a plurality of partialconduits or stents extending from a coronary artery partially into themyocardium.

[0066]FIG. 13 is a schematic front elevational view of a human heart,showing an improvement in the myocardial revascularization of FIG. 12.

[0067]FIGS. 14A and 14B are schematic cross-sectional views of a humanheart, showing successive steps in an artificial myocardialrevascularization procedure, resulting in a plurality of conduits orstents extending from a left ventricle of the heart at least partiallyinto the myocardium.

[0068]FIG. 15 is a schematic partial cross-sectional view of a humanheart, illustrating a modification to the artificial myocardialrevascularization of FIG. 14B.

[0069]FIG. 16 is a schematic partial cross-sectional view of a humanheart, illustrating a heart provided in a left ventricle with implantsor plugs.

[0070]FIG. 16A is a schematic partial cross-sectional view of a conduitor plug, having therapeutic materials applied thereto.

[0071]FIG. 16B is a side view of a biodegradable conduit or stentpositioned within the myocardium, with the coronary artery andmyocardium shown cut-away.

[0072] FIGS. 16C-16F are schematic, cross-sectional views of theexternal insertion of an absorbable intramyocardial plug in themyocardium.

[0073] FIGS. 16G-16I are schematic, cross-sectional views of theinsertion of absorbable intramyocardial plugs in the myocardium via theleft ventricle.

[0074] FIGS. 16J-16N are schematic, cross-sectional views of theexternal insertion of absorbable intramyocardial plugs used to form aconduit or shunt through the myocardium from the left ventricle to thecoronary artery.

[0075] FIGS. 16O-16S are schematic, cross-sectional views of theexternal insertion of absorbable intramyocardial plugs in themyocardium.

[0076]FIG. 17 is a small scale cross-sectional view of a heart with ablockage in the coronary artery and illustrating a self-insertingconduit.

[0077]FIG. 18 is a close-up perspective view of one embodiment of thedevice of FIG. 17 shown implanted in the myocardium, with the coronaryartery, myocardium and left ventricle of the heart shown cut-away.

[0078]FIG. 18A is a schematic partial cross-sectional view of aself-inserting conduit, having dual prongs in the head or flange thereofto prevent rotation.

[0079] FIGS. 19A-C illustrate a method for implanting the conduit deviceof FIG. 17.

[0080] FIGS. 20A-B illustrate an alternate method for implanting theconduit device of FIG. 17.

[0081]FIG. 21 is a small scale cross-sectional view of a heart with ablockage in the coronary artery, and further illustrating anotherembodiment of the bypass device of this embodiment;

[0082]FIG. 22 is a close-up cross-sectional view of the blockage in thecoronary artery and illustrating in greater detail the bypass device ofthe present invention;

[0083] FIGS. 22A-22B are schematic partial cross-sectional views ofconduits similar to that described in FIG. 22 illustrating alternativeblood flow embodiments.

[0084]FIG. 23 is a perspective view of the bypass device and conduit;

[0085]FIG. 24 is a close-up view of a combination access/shunt conduitdevice having a distal tip;

[0086]FIG. 25 is a perspective view of an alternative embodiment of acombination access/shunt device conduit;

[0087] [FIG. 26 is reserved]

[0088]FIG. 27 is a perspective view of a third combination access/shuntembodiment which has a tapered configuration;

[0089]FIG. 28 is a perspective view of a fourth combination access/shuntembodiment with dual distal tips.

[0090]FIG. 29 is a perspective view of a conduit or shunt deviceaccording to a fifth embodiment of a combination access/shunt;

[0091]FIG. 30 is a perspective view of a conduit or shunt deviceaccording to a sixth embodiment of a combination access/shunt;

[0092]FIG. 31 shows the shunt device of FIG. 29 in cross-section;

[0093]FIG. 32 is a close-up cross-sectional view of a coronary arteryblockage and the myocardium of a patient and the shunt device accordingto FIG. 29;

[0094]FIG. 33 is a perspective view of a side-by-side bypass device;

[0095]FIG. 33A is a schematic cross-sectional view illustrating thecoronary bypass system which is more parallel to the coronary artery.

[0096]FIG. 34 is a perspective view of another side-by-side bypassembodiment;

[0097]FIG. 35 is a perspective view of a third side-by-side bypassembodiment;

[0098] [FIG. 36 is reserved]

[0099]FIG. 37 is a close-up cross-sectional view of a coronary arteryand the myocardium of a patient and the shunt device according to FIG.34;

[0100]FIG. 38 is a close-up cross-sectional view of a coronary artery ofa patient and the shunt device according to FIG. 36.

[0101] FIGS. 39A-B illustrate the temporary use of a stent during acoronary bypass procedure.

[0102]FIGS. 40 and 40A-40Q show a variety of members for securingsegments of tissue to each other, as well as conduit members.

[0103]FIG. 41 shows a conduit of variable wall thickness.

[0104]FIGS. 42, 43, 44A-44C, and 45 show conduits designed to takeadvantage of flow resistance to facilitate flow control.

[0105] FIGS. 46, 47A-47D, 48, 48A-48C, and 49 show curved conduits thatdirect blood flow downstream in a direction that is substantiallyparallel to the bloodstream in the vessel.

[0106] FIGS. 50A-50C and 51A-51D show a variety of conduits of a latticeconstruction.

[0107]FIG. 52 shows a conduit having a T-like distal portion.

[0108]FIG. 53 shows a conduit that has an articulating distal portion.

[0109]FIG. 54 shows a conduit that has an elastomeric distal anchoringarm.

[0110] In the drawings, the same reference designations are used todesignate the same objects. The word “distal” when used hereindesignates an instrument end which is spaced from the surgeon,radiologist or other operator. The physical relation of the instrumentto the patient is not determinative.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0111] The principles of the present invention are not limited to leftventricular conduits, and apply to conduits for communicating bodilyfluids from any space within a patient to another space within apatient, including any mammal. Furthermore, such fluid communicationthrough the conduits is not limited to any particular direction of flowand can be antegrade or retrograde with respect to the normal flow offluid. Moreover, the conduits may communicate between a bodily space anda vessel or from one vessel to another vessel (such as an artery to avein or vice versa). Moreover, the conduits can reside in a singlebodily space so as to communicate fluids from one portion of the spaceto another. For example, the conduits can be used to achieve a bypasswithin a single vessel, such as communicating blood from a proximalportion of an occluded coronary artery to a more distal portion of thatsame coronary artery.

[0112] In addition, the conduits and related methods can preferablytraverse various intermediate destinations and are not limited to anyparticular flow sequence. For example, in one preferred embodiment ofthe present invention, the conduit communicates from the left ventricle,through the myocardium, into the intrapericardial space, and then intothe coronary artery. However, other preferred embodiments are disclosed,including direct transmyocardial communication from a left ventricle,through the myocardium and into the coronary artery. Thus, as emphasizedabove, the term “transmyocardial” should not be narrowly construed inconnection with the preferred fluid communication conduits, and othernon-myocardial and even non-cardiac fluid communication are preferred aswell. With respect to the walls of the heart (and more specifically theterm “heart wall”), the preferred conduits and related methods arecapable of fluid communication through all such walls including, withoutlimitation, the pericardium, epicardium, myocardium, endocardium,septum, etc.

[0113] The bypass which is achieved with certain preferred embodimentsand related methods is not limited to a complete bypass of bodily fluidflow, but can also include a partial bypass which advantageouslysupplements the normal bodily blood flow. Moreover, the occlusions whichare bypassed may be of a partial or complete nature, and therefore theterminology “bypass” or “occlusion” should not be construed to belimited to a complete bypass or a complete occlusion but can includepartial bypass and partial occlusion as described.

[0114] The preferred conduits and related methods disclosed herein canalso provide complete passages or partial passages through bodilytissues. In this regard, the conduits can comprise stents, shunts, orthe like, and therefore provide a passageway or opening for bodily fluidsuch as blood. Moreover, the conduits are not necessarily stented orlined with a device but can comprise mere tunnels or openings formed inthe tissues of the patient.

[0115] The conduits of the present invention preferably comprise bothintegral or one-piece conduits as well as plural sections joinedtogether to form a continuous conduit. In this regard, the anastomoticdevices and methods utilized in connection with the various embodimentsof the present invention are to be broadly construed to relate toconnections of these various components. The present conduits can bedeployed in a variety of methods consistent with sound medical practiceincluding vascular or surgical deliveries, including minimally invasivetechniques. For example, various preferred embodiments of delivery rodsand associated methods are disclosed. In one embodiment, the deliveryrod is solid and trocar like. It may be rigid or semi-rigid and capableof penetrating the tissues of the patient and thereby form the conduit,in whole or in part, for purposes of fluid communication. The deliveryrod may be an incising instrument such as a laser or a drill. In otherpreferred embodiments, the delivery rods may be hollow so as to form theconduits themselves (e.g., the conduits are preferably self-implantingor self-inserting) or have a conduit mounted thereon (e.g., the deliveryrod is preferably removed leaving the conduit installed). Thus, thepreferred conduit device and method for installation is preferablydetermined by appropriate patient indications in accordance with soundmedical practices.

[0116] Further details regarding conduits and conduit delivery systemsare described in copending patent applications entitled DELIVERY METHODSFOR LEFT VENTRICULAR CONDUIT [Attorney Docket No. PERCAR.003CP1],DESIGNS FOR LEFT VENTRICULAR CONDUIT [Attorney Docket No. PERCAR.013A],LEFT VENTRICULAR CONDUIT WITH BLOOD VESSEL GRAFT [Attorney Docket No.PERCAR.005A], VALVE DESIGNS FOR LEFT VENTRICULAR CONDUIT [AttorneyDocket No. PERCAR.006A], and BLOOD FLOW CONDUIT DELIVERY SYSTEM ANDMETHOD OF USE [Attorney Docket No. PERCAR.040A], filed on the same dayas the present application, and U.S. Pat. Nos. 5,429,144 and 5,662,124,the disclosures of which are all hereby incorporated by reference intheir entirety.

[0117] Conduits Utilizing Intrapericardial Space

[0118] In a transmyocardial coronary artery bypass operation illustratedin FIGS. 1A-1E, a catheter 12 is inserted over a guidewire (notillustrated) through the vasculature of a patient and particularlythrough the aorta AO into the left ventricle LV of the patient's heartPH. (Although the embodiments described herein are discussed withrespect to the left ventricle LV, they may also be applied to the rightventricle RV and the right and left atria.) Upon arrival of a distal endof catheter 12 in left ventricle LV, the guidewire is withdrawn and asurgical incising instrument 14 such as a light-transmitting opticalfiber is inserted through catheter 12. The catheterization procedure ismonitored via conventional radiographic techniques or, alternatively,via a CAT scanner or MRI machine.

[0119] Upon ejection of a distal tip of optical fiber 14 from catheter12 into left ventricle LV, the fiber tip is placed into contact with aheart wall HW of the patient at a predetermined location downstream ofan arterial blockage BL in the coronary artery CA of the patient, asillustrated in FIG. 1A. A laser source 16 is then activated to transmitmonochromatic electromagnetic radiation along optical fiber 14 to heartwall HW. The distal end of fiber 14 is pushed through heart wall HW,with the radiation being continuously or periodically transmittedthrough optical fiber 14, thereby forming a transmyocardial passageway18 in heart wall HW (FIG. 1B).

[0120] After the formation of passageway 18, optical fiber 14 iswithdrawn from catheter 12 and replaced with a guidewire 20 (FIG. 1C).In addition, catheter 12 is pushed in a forward direction throughpassageway 18 so that a distal end portion of the catheter extendsoutwardly from passageway 18 into an intrapericardial space IS. A shunt22 made of flexible biocompatible material such as polyethylene orGORTEX™ is then passed over guidewire 20 and through catheter 12. Atthis juncture, a forceps instrument 24 (FIGS. 1C and 1D) inserted intothe patient via a pericardioscopic cannula or port (not shown) orthrough an open incision (not shown) is used to grasp shunt 22 anddirect a free end of the shunt to an anterior wall AW of coronary arteryCA, as illustrated in FIG. 1D. A laser instrument 26 is then used toattach the free end of shunt 22 to the anterior wall AW of coronaryartery CA. At this point in the operation, there is no avenue ofcommunication between left ventricle LV and coronary artery CA.

[0121] After the attachment of shunt 22 to anterior wall AW of coronaryartery CA, optical fiber 14 is again inserted through catheter 12 andthrough shunt 22 to anterior wall AW of coronary artery CA. Laser source16 is temporarily activated to form an aperture in anterior wall AW ofcoronary artery CA inside shunt 22, thereby establishing atransmyocardial coronary artery bypass path from left ventricle LV intothe coronary artery downstream of blockage BL as illustrated in FIG. 1E.After the formation of the aperture in coronary artery CA, fiber 14 iswithdrawn from shunt 22 and catheter 12 is withdrawn from heart wall HW.Optical fiber 14 may be used at that time (or previously) to attach anupstream end of shunt 22 to heart wall HW at left ventricle LV. Theoptical fiber 14 and catheter 12 are then extracted from the patient.The deployed shunt 22 extends from left ventricle LV through heart wallor myocardium HW to anterior wall AW of coronary artery CA, with amiddle or intermediate portion (not separately designated) of shunt 22being disposed in intrapericardial space IS.

[0122]FIG. 2 depicts a transmyocardial coronary artery bypass similar tothat shown in FIG. 1E, except that a different shunt 28 is used. Shunt28 is provided at opposite ends with flanges 30 and 32 in the form ofannular disks. These flanges 30 and 32 facilitate the attachment ofshunt 28 to the heart wall HW at left ventricle LV and to anterior wallAW of coronary artery CA, respectively. The attachment of flanges 30 and32 to heart wall HW and coronary artery CA may be effectuated by laserinstrument 26 and/or by other techniques including gluing and suturing.Shunt 28 is installed in the manner described above with reference toFIGS. 1A-1E.

[0123] The structure of shunt 28, as well as different uses thereof, isdescribed and illustrated in U.S. Pat. No. 5,470,320, the disclosure ofwhich is hereby incorporated by reference.

[0124]FIG. 3 shows a modification of the transmyocardial coronary arterybypass of FIG. 1E. The downstream end of shunt 22 is attached toanterior wall AW of coronary artery CA via sutures 34. A stent 36 with aone-way valve 38 is placed inside an upstream portion of shunt 22located within heart wall or myocardium HW. Stent 36 functions to clampthe upstream end of shunt 22 to heart wall HW. One-way valve 38 permitsblood to flow from ventricle LV to coronary artery CA during systole andprevents backflow to ventricle LV during diastole. Where shunt 22 isinstalled without stent 36, shunt 22 may be provided with an integralone-way valve (not illustrated). Stent 36 is generally introduced intoheart PH in a collapsed configuration through a catheter. Stent 36 maybe predisposed inside the upstream end portion of shunt 22 and insertedtherewith into heart PH. Alternatively, stent 36 may be inserted intoshunt 22 after the shunt has been passed through passageway 18 andbefore or after the attachment of the downstream end of shunt 22 toanterior wall AW of coronary artery CA. Stent 36, and other stents andshunts disclosed herein, may be provided with outwardly projecting barbs(not illustrated) for anchoring the stent or shunt to the myocardium.

[0125] In another variation (not illustrated) of the transmyocardialcoronary artery bypass of FIG. 1E, shunt 22 has an upstream portionwhich is a stent. The stent is substantially coextensive with or smallerthan passageway 18 and is accordingly lodged completely withinpassageway 18 upon installation of the shunt 22. The remainder of theshunt 22 is made of a continuous, essentially impermeable biocompatiblefilm material, as in the embodiment discussed above.

[0126] As illustrated in FIG. 4, another modification of thetransmyocardial coronary artery bypass of FIG. 1E includes the insertionof a downstream end portion 40 of shunt 22 through an aperture 42 formedin anterior wall AW of coronary artery CA downstream of blockage BL.Clearly, in this bypass procedure, aperture 42 is formed in coronaryartery CA prior to the joining of the downstream end portion 40 of shunt22 and coronary artery CA. Aperture 42 is formed by an incisinginstrument (not shown) such as a laser or a scalpel blade which isinserted into intrapericardial space IS either through apericardioscopic cannula or port (not shown) or through an openincision. Shunt 22 may be attached, by laser welding, glue or sutures,to coronary artery CA at aperture 42. As discussed hereinabove withrespect to the embodiment of FIG. 1E, an intermediate or middle portion44 of shunt 22 is disposed inside intrapericardial space IS upondeployment of shunt 22. A brace 48, for example, in the form of a patch(compare with FIG. 13), may be disposed over middle portion 44 of shunt22 and attached to heart PH, to support the shunt 22 against possibledislodgment owing to the hydraulic forces of blood flow and themechanical forces of myocardium contraction. Brace or patch 48, andsimilar braces or patches disclosed herein, is made of a strongbiocompatible material such as KEVLAR™, polytetrafluoroethylene,silicone, etc.

[0127]FIG. 5 illustrates the shunt-implemented transmyocardial coronaryartery bypass of FIG. 4, with a one-way valve 50 being provided at theupstream end of shunt 22 for permitting blood flow from ventricle LVinto coronary artery CA during systole and for preventing blood flowfrom coronary artery CA toward ventricle LV during diastole.

[0128] Conduit Configurations

[0129]FIG. 5A illustrates a human heart PH, showing more particularlythe left anterior descending coronary artery CA. The technical challengepresented herein is placing a conduit accurately and aligned properlybetween the left ventricle LV and the coronary artery CA. A conduit 49is shown in FIGS. 5A-5C comprising two separate pieces, namely an accessport 51 which punctures through the heart wall HW, including themyocardium, to the left ventricle LV, and an anastomosed segment 53. Toplace the conduit 49, the access port 51 is inserted into the heart wallHW from the outside of the heart PH, preferably adjacent but notnecessarily through the coronary artery CA. Flange 55 determines theposition of the port 51 by pressing against the outside of the heart PH,and the port extends into the left ventricle LV with a lumen 57extending therethrough. The end of the port 51 on the outside of theheart wall HW may be curved as shown in FIG. 5C. After the port 51 isinserted, the port is connected to the artery CA preferably using asegment 53 which is more preferably an artificial graft. The locationwhere the segment 53 is anastomosed to the coronary artery maypreferably be downstream of a blockage (not shown) in the coronaryartery CA.

[0130] The embodiment of FIGS. 5A-5C is advantageous in that it does notrequire extremely accurate placement of the port 51 into the heart PH.This is especially important because during a beating heart procedureplacement of a device through the heart PH may be difficult. Morespecifically, as shown in FIGS. 5A-5C, the port 541 need not bepositioned at a very precise position through or adjacent the coronaryartery CA. Rather, the port 51 need only be placed near the coronaryartery CA, and the graft segment 53 is used to connect the port 51 tothe coronary artery CA. It will be appreciated that multiple conduitsmay be made to the artery CA.

[0131] As depicted in FIGS. 6A and 6B, a transmyocardial coronary arterybypass is implemented by a conduit or shunt member 52 provided at anupstream end with a one-way valve 54. Shunt member 52 extends directlyfrom left ventricle LV through heart wall HW into coronary artery CA andincludes an upstream portion 56 disposed within heart wall or myocardiumHW and a downstream portion 58 disposed in coronary artery CA. Shuntmember 52 may have a tapered form which narrows down in a downstreamdirection so that downstream portion 58 is of smaller cross-section thanupstream portion 56. Upstream portion 56 may take the form of a stentwhich is expanded from a collapsed insertion configuration to anexpanded use configuration to lock or clamp shunt member 52 to apassageway 60 formed in heart wall or myocardium HW prior to theinsertion of shunt member 52. Downstream portion 58 is made of acontinuous, essentially impermeable biocompatible film material. Inaddition, upstream portion 56 may be flexible to an extent so as toexpand, if necessary, during diastole (FIG. 6B) to accommodate somebackflow. It will also be noted in connection with FIG. 6B, the upstreamportion 56 also acts as a reservoir to accumulate blood during systolewhich is then passed into the coronary artery CA during diastole.

[0132] Shunt 52 is curved and bears the force of the blood ejected fromleft ventricle LV through passageway or channel 60 during systole.

[0133] Other one way valve embodiments are shown in FIGS. 6C-6H and areparticularly useful for directing laminar flow and controlling the flowof blood. FIGS. 6C and 6D show the open and closed positions,respectively, of a conduit 700. The conduit comprises a relatively soft,pliable portion 704 and a harder, firmer portion 708. In the openconfiguration (FIG. 6C), blood flows out of a hole 712 in the conduit700 and into the left ventricle LV. The softer portion 704 has aresiliency such that a hood or flap portion 716 closes during diastole,thereby blocking the flow of blood.

[0134]FIGS. 6E and 6F show another one way valve conduit embodiment 720that comprises soft and hard portions 724 and 728, respectively. Thesoft portion 724 includes a flap portion 732 having a series of slits736 therein which may be spaced equidistantly from each other as shown,or alternatively, the slits may be spaced unequally from each other. Theresiliency of the conduit 720 is such that it is open during systole(FIG. 6F) but closes partially during diastole (FIG. 6F).

[0135]FIGS. 6G and 6H show another one way valve conduit embodiment 740comprising soft and hard portions 744 and 748, in which a single slit752 is formed in the soft portion 744. As in embodiments 6C-6D and6E-6F, the resiliency of the soft portion is such that the conduit 740acts as a one-way valve, with the conduit opening during systole andpartially closing during diastole. Further, conduits (not shown) havingan opening for blood flow, but no slits, may be used in which theportion of the conduit around the opening partially or completelycollapses (closes) during diastole, but is at least partially openduring systole.

[0136] As illustrated in FIG. 7, the deployment or installation of shunt52 in an intravascular procedure requires instrumentation for enablingthe precise locating of the coronary artery CA with respect to possibleinsertion points in left ventricle LV. To that end, a first catheter 62is utilized which is provided at a distal end with an electroacoustictransducer (not illustrated) for converting an electrical signal ofultrasonic frequency to a mechanical pressure wave which is transmittedthrough a posterior wall PW of coronary artery CA and heart wall ormyocardium HW. Catheter 62 and particularly the electroacoustictransducer (not shown) is operatively connected to an ultrasonic wavegenerator 64. Another catheter 66 is also inserted through aorta AO (andover a conventional guidewire, not illustrated). This second catheter 66is introduced into left ventricle LV and is provided at a free end withan acoustoelectric transducer (not shown) for detecting pressure wavesin an ultrasonic frequency range. Catheter 66 and its acoustoelectrictransducer are operatively connected to an ultrasonic wave analyzer 68which calculates the location of the distal tip of catheter 62 relativeto the distal tip of catheter 66 and thus provides feedback to a surgeonor an insertion device for determining an insertion point and insertionangle for surgical incising instrument such as optical fiber 14 (FIG.1A).

[0137] Several shunt members 22 or 52 may be necessary in cases ofmultiple coronary artery blockages. These multiple shunt members eachtap into the coronary artery at a point downstream of a respectiveblockage.

[0138] As depicted in FIG. 8, a transmyocardial stent 70 for maintaininga circulation path between left ventricle LV of patient's heart PH andcoronary artery CA is curved in the longitudinal or flow direction toprovide an arcuate flow path. This curvature serves to deflect thehydraulic forces from a direction substantially perpendicular tocoronary artery CA to a direction substantially parallel to coronaryartery CA. This deflection serves to prevent coronary artery dilatationand to protect anterior wall AW of artery CA from the substantialhydraulic forces generated during systole. Thus, this deflection servesto control the flow of the blood through the stent 70 during systole.Moreover, since the stent 70 narrows and curves towards the coronaryartery CA, it serves to prevent or minimize backflow into the stent 70during diastole, thus obviating the need for a valve 72. Stent 70 may beoptionally provided with a one-way valve 72 and may be deployed asdiscussed above with reference to FIG. 7. Curved stent 70 may be used asupstream portion 56 of shunt member 52 or in place of stent 36 (FIG. 3)or as an upstream portion of shunt 22. FIGS. 8A and 8B illustratefurther arcuate stent embodiments for maintaining circulation betweenthe left ventricle LV and the coronary artery CA. As in FIG. 8, theembodiments of FIGS. 8A and 8B include a transmyocardial stent 70 thatis curved in the longitudinal or flow direction to provide an arcuateflow path.

[0139]FIGS. 8C and 8D illustrate how a catheter 800 may be introducedinto the coronary artery CA (FIG. 8C) or on both sides of the heart wall(FIG. 8D) for boring out a portion of the heart wall HW to form anhourglass-shaped portion 804 within the heart wall HW. The hourglassshaped portion 804 acts to create a valve effect so that blood is atleast partially blocked during diastole.

[0140] As seen in FIGS. 8E and 8F, a stent 808 may be positioned withinthe heart wall HW. As shown in FIG. 8E, the stent 808 is driven towardsa closed position during diastole, whereas FIG. 8F shows the openposition of the stent during systole. FIGS. 8G and 8H show an embodimentanalogous to FIGS. 8E-F, except that a stent 812 is used that has avarying thickness. Using a stent 812 of nonconstant thickness has theeffect of accentuating the deflection of the stent 812 at its centralportion 814 relative to that at the outer portions 816 of the stent (atits ends).

[0141] Other stent designs may be used like the parallelpiped shapedstents 818 of FIGS. 8L-M (which may include a movable flap portion 820for controlling the flow of blood) or the stents 824 illustrated inFIGS. 8N-O (which likewise may include a movable flap 828 forcontrolling the flow). FIGS. 81-8K show another embodiment whichincludes a conically-shaped stent 832 whose base is located on thecoronary artery side. The stent 832 includes rims 834 and 836 forsecuring the stent 832 to the heart wall HW.

[0142]FIG. 8P illustrates an embodiment of a stent 850 which, like theembodiment of FIG. 8, maintains a circulation path between the leftventricle LV of patient's heart PH and coronary artery CA. The stent 850has a lumen 852 therein which is curved, thereby deflecting hydraulicforces to control the flow of the blood through the stent 850 duringsystole. Further, the lumen 852 narrows and curves towards the coronaryartery CA, which reduces backflow into the stent 850 during diastole andreduces the need for a valve. Nevertheless, the stent 850 may beoptionally provided with a one-way valve 72 and may be deployed asdiscussed above with reference to FIG. 7. Further, the stent 850 may beused as upstream portion 56 of shunt member 52 or in place of stent 36(FIG. 3) or as an upstream portion of shunt 22. Unlike its counterpartin FIG. 8, however, the lumen 852 of FIG. 8P is oriented within thestent 850 such that the lumen 852 joins the coronary artery CA at anoblique angle when the stent 850 is oriented perpendicular to thecoronary artery CA. This aids the practitioner in the proper positioningof the lumen 852, and insures that the lumen 852 will be oriented withrespect to the coronary artery CA as shown in FIG. 8P when a flange 854of the stent 850 is positioned against the coronary artery CA. Further,the stent 850 of FIG. 8P may advantageously have an outer dimension thatis substantially constant in cross section.

[0143] A shunt or stent 74 may be provided with a pressure sensor 76and/or a flow sensor 78, as illustrated in FIG. 9. Sensors 76 and 78 areattached to or incorporated into a wall 80 of shunt or stent 74 and haveoutputs operatively connected to a transmitter 82 which is also attachedto or incorporated into shunt or stent wall 80. Output signals fromsensors 76 and 78 which encode data pertaining to pressures and flowrates are relayed to a receiver 84 via transmitter 82. Transmitter 82may be wireless or connected by a wire 86 to receiver 84. The pressureand flow rate data collected via sensors 76 and 78 are useful formonitoring the effectiveness of the implanted stents or shunts for anyparticular patient and thereby determining whether additional stents orshunts may be necessary for that patient. Receiver 84 may be physicallylocated on a chest of the patient or otherwise nearby.

[0144]FIG. 9A illustrates a cross-section of the heart illustrating astent 900 having incorporated therein a sensor 904 (shown in FIG. 9B)similar to the sensors described above in connection with FIG. 9. Thesensor may be incorporated into the wall of the stent 900 as illustratedin FIG. 9B or may be associated with a stent in some other fashion. Thesensor 904 may advantageously transmit an output signal which encodesdata with respect to pressures and flow rates. For example, bloodpressure during both systole and diastole may be monitored, and thesensor 904 may be used to indicate when the blood flow (or pressure) isdecreasing or when the blood flow (or pressure) falls beneath a certainlevel. As shown in FIG. 9C, a conduit 910 having a sensor therein may beused between two vessels, such as an aorta 912 and a vein 914.

[0145] Posterior Wall Access

[0146] As illustrated in FIGS. 10A-10C, a transmyocardial coronaryartery bypass may be performed from outside the patient's vascularsystem. An incising instrument 88 such as a laser or a drill is insertedpericardioscopically or through an open incision into theintrapericardial space IS and is operated to bore a passageway 90 in theheart wall or myocardium HW via the coronary artery CA, as shown in FIG.10A. Passageway 90 (FIG. 10B) extends through heart wall HW andposterior wall PW of coronary artery CA and is aligned with an aperture92 formed in anterior wall AW of coronary artery CA by the incisinginstrument 88.

[0147] Upon the formation of passageway 90, a stent 94 (FIG. 10C) isinserted in a collapsed configuration into the passageway and thenexpanded. Stent 94 may be inserted from outside the patient's vascularsystem, either through an open incision in the patient's chest orthrough a pericardioscopic cannula or port. Alternatively, stent 94 maybe placed via a catheter 96 inserted through the vascular systemincluding the aorta AO and the left ventricle LV. As in all cases ofstent implantation described herein, stent 94 serves to maintainpassageway 90 in an open state, i.e., prevents the closure of passageway90 by muscular contraction forces during systole and, in the longerterm, by natural healing processes of the myocardium.

[0148] After the formation of passageway 90 and after the installationof stent 94 via an extravascular operation, aperture 92 is closed, viasutures (not shown) and/or via a plug 98 (FIG. 10C) or patch which isstitched or laser bonded to anterior wall AW of coronary artery CA. Ifstent 94 is placed via an intravascular operation, aperture 92 ispreferably closed prior to the disposition of the stent insidepassageway 90. A brace 100 in the form of a patch is optionally placedover plug 98 and fastened to heart PH via sutures, glue or welding tosupport the plug against possible dislodgment under blood pressureforces.

[0149]FIG. 11 illustrates a triple transmyocardial coronary arterybypass wherein a plurality of stents 94, 94 a and 94 b are placed inrespective passageways (not separately designated) extending throughheart wall or myocardium HW and posterior wall PW of coronary artery CA.The passageways are formed and the stents 94, 94 a and 94 b inserted asdescribed hereinabove with reference to FIGS. 10A-10C. Plugs 98, 98 aand 98 b are positioned in respective apertures (not separatelydesignated) which are formed, as discussed above, in alignment with thepassageways of stents 94, 94 a and 94 b. A brace 102 in the form of apatch is optionally placed over plugs 98, 98 a and 98 b and fastened toheart PH via sutures, glue or laser welding.

[0150]FIG. 12 depicts a modification of the transmyocardial coronaryartery bypass of FIG. 11, wherein passageways 104 a, 104 b, 104 c and104 d are formed by the extravascular technique discussed above withreference to FIGS. 10A-10C but which extend through posterior coronaryartery wall PW and only part of the heart wall or myocardium HW fromcoronary artery CA. Stents 106 a, 106 b, 106 c and 106 d are insertedinto respective passageways 104 a, 104 b, 104 c and 104 d via anextravascular operation. Thereafter, plugs 108 a, 108 b, 108 c and 108 dare inserted into or over respective apertures in anterior coronaryartery wall AW aligned with passageways 104 a, 104 b, 104 c and 104 dand stents 106 a, 106 b, 106 c and 106 d. As illustrated in FIG. 13, apatch 110 may be placed over coronary artery CA and particularly overplugs 108 a, 108 b, 108 c, 108 d and attached via sutures 112 to heartPH to brace the plugs against dislodgment under systolic and diastolicblood pressures.

[0151]FIGS. 14A and 14B depict steps in a transmyocardialrevascularization procedure. An incising instrument 114 such as a laserfiber or a drill is inserted in an extravascular procedure through anopen chest incision or a pericardioscopic cannula or port and is used toform a channel or passageway 116 in heart wall or myocardium HW throughthe epicardium (not shown). A stent 118 is inserted into channel 116 ina collapsed configuration via an intravascularly deployed catheter 120or in an extravascular operation. A plug 122 is inserted into an outerend of channel 116 to close off that outer end. Plug 122 may be attachedto the epicardium of heart PH via a laser instrument 123 or via sutures(not shown). Several channels 116, 116 a and 116 b may be formed andprovided with respective stents 118, 118 a and 118 b and respectiveplugs 122, 122 a and 122 b, as illustrated in FIG. 15. A patch 124 maybe placed over plug 122 or plugs 122, 122 a and 122 b and attached viasutures 126 to heart wall HW.

[0152] Myocardial Plugs

[0153] The various conduits or stents disclosed herein may be providedwith a layer of polymeric material carrying a biochemical composition,e.g., angiogenesis factor or the nucleic acid instructions therefor, forgenerating, stimulating, and enhancing blood vessel formation. Asillustrated in FIG. 16, plugs 128 may be inserted into a patient's heartwall or myocardium HW from inside the left ventricle LV or rightventricle RV via an intravascularly deployed catheter (not shown).Alternatively, the plugs may be inserted into the heart wall ormyocardium HW from outside of the heart in an open incision orpericardioscopic operation (not shown). In either case, the plugs carryangiogenesis factor, or the nucleic acid instructions therefor, forgenerating, stimulating, and enhancing vascular generation and growth.The angiogenesis factor is gradually released from the plugs, or stents,in time release fashion, to optimize the stimulation of vascular growth.

[0154]FIG. 16A is a schematic partial cross-sectional view of atriangular-shaped conduit comprising a plug 940 or stent or the like andhaving, for example, multiple factors applied thereto such as growthfactors, genes, drugs, etc. The rate at which an applied factor isreleased may be controlled through appropriate configuration of the plug940, e.g., by controlling its porosity.

[0155] If desired, the stent or conduit of the present invention can beformed of biodegradable or bioabsorbable materials and/or used todeliver drugs directly into the myocardium and the coronary circulation.Such a stent 952 is illustrated in FIG. 16B. The biodegradable stent 952can extend only partially through the heart wall HW as illustrated inFIG. 16B, but can also extend entirely through from the left ventricleLV to the coronary artery CA. Once positioned in the heart wall HW, thestent 952 degrades, dissolves or is absorbed over time to release drugs,genes, angiogenesis or growth factors, or other pharmaceutical compoundsdirectly into the heart wall HW and the coronary artery CA, as shown bythe arrows in FIG. 16B. Bioabsorbable materials include, but are notlimited to, polymers of the linear aliphatic polyester and glycolidefamilies, such as polylactide and polyglycolide.

[0156] Such a stent is also illustrated in FIGS. 16C-16F. FIG. 16Cillustrates the external insertion of a solid, but absorbable stent orplug 1100. A delivery device 1102, such as a thoroscope bearing theintramyocardial plug 1100 is inserted into the heart wall HW at a sitedistal to the blockage BL in the coronary artery CA as shown in FIG.16D. The insertion site in the heart wall HW is permanently closed usingsutures 1104, a plug, laser coagulation or similar means, as shown inFIG. 16E. This allows for myocardial revascularization. As the plug 1100is absorbed, blood flows from the coronary artery CA into the passagewayformed by the absorbed plug 1100. This results in the ischemicmyocardial area being revascularized. Alternatively, as illustrated inFIGS. 16E and 16F, the intramyocardial plug 1100 can be inserted throughthe heart wall HW such that it extends into the left ventricle LV. Asthe plug 100 is absorbed by the body, there remains a space or channel1106 in the heart wall HW that perfuses with oxygenated blood from theleft ventricle LV. This channel 1106 acts as do the channels formed inthe heart during percutaneous transmyocardial revascularization (PTMR),allowing the heart muscle to be exposed to additional oxygenated blood.

[0157] FIGS. 16G-16I illustrate an alternative means for delivering anabsorbable plug 1110 into the heart wall HW. FIG. 16G illustrates thedelivery of multiple plugs 1110 using a catheter 1112 threaded throughthe patient's vasculature and into the left ventricle LV of the heart.The plug 1110 is inserted into the myocardial wall as shown is FIG. 16H.The plug 1110 is absorbed over time, leaving an opening or channel 1114in the heart wall HW (FIG. 16I) that perfuses with oxygenated blood fromthe left ventricle LV. This channel 1114 acts as do the channels formedin the heart during percutaneous transmyocardial revascularization(PTMR), allowing the heart muscle to be exposed to additional oxygenatedblood.

[0158] Turning now to FIGS. 16J-16N, there is shown the insertion of anabsorbable intramyocardial plug 1120 that achieves the same result as astent. The plug 1120 is inserted through the posterior wall of thecoronary artery CA, either externally as described below, or internallyusing a delivery catheter threaded through the aorta AO and the coronaryartery CA. External insertion is illustrated in FIGS. 16J-M. In FIG.16J, there is illustrated a thoroscope 1122 having the absorbable plug1120 at its distal end inserted into the chest of the patient, until itreaches the heart. The plug 1120 is inserted through the posterior wallof the coronary artery CA and into the heart wall HW (FIGS. 16K and16L). As the delivery device 1122 is removed, the hole in the anteriorwall of the coronary artery CA is closed, using sutures 1124, staples,laser coagulation, plugs such as GELFOAM, adhesives such ascyanoacrylate, or similar closure means, as illustrated in FIG. 16M. Asthe plug 1120 is absorbed, a shunt 1126 is formed between the leftventricle LV and the coronary artery CA, which allows for the passage ofblood (FIG. 16N).

[0159] FIGS. 16O-16S illustrate the insertion of absorbableintramyocardial plugs 1130 which result in the perfusion of the heartwall HW with blood flowing through the coronary artery CA. In FIG. 16O,there is illustrated a thoroscope 1132 having the absorbable plug 1130at its distal end being inserted into the chest of the patient, until itreaches the heart. The plug 1130 is inserted through the posterior wallof the coronary artery CA, and only partially through the heart wall HWsuch that it stops before reaching the left ventricle LV of the heart(FIG. 16Q). As the delivery device 1132 is removed, the hole in theanterior wall of the coronary artery CA is closed, using sutures 1134,staples laser coagulation, plugs, such as GELFOAM, adhesives such ascyanoacrylate or similar closure means, as illustrated in FIG. 16R. Theplug 1130 is absorbed over time, leaving an opening or channel 1136 inthe heart wall HW (FIG. 16S) that perfuses with oxygenated blood fromthe coronary artery CA. The channel 1130 acts as do the channels formedin the heart during percutaneous transmyocardial revascularization(PTMR), allowing the heart muscle to be exposed to additional oxygenatedblood.

[0160] It is to be appreciated that the drawings herein are schematic.The stents and shunt portions in the forms of stents described hereinmay have a conventional wire infrastructure not shown in the drawings.Alternatively, the stents may be made of an elastic material having aninternal spring constant permitting the stent to be temporarilycollapsed and then returned to an opened configuration.

[0161] Intravascular or extravascular incising instruments disclosedherein for use in forming passageways or channels in the myocardium maybe contact lasers or rotating or reciprocating drills. Other drilling orcutting instruments suitable for forming channels or tunnels may be usedalternatively or additionally. Such instruments may take the form ofultrasonic cavitation devices, chemical devices for dissolving tissues,or heat treatment (electrocautery) devices.

[0162] Although suturing, gluing and laser welding are discussed hereinfor attaching plugs and reinforcement patches or braces to the cardiactissues, equivalent alternatives to these techniques include staplingand tacking. Also, apertures in the epicardium or coronary artery may beclosed without plugs or patches, for example, by the direct applicationof sutures or staples or by coagulation (electrical, thermal or laser).

[0163] It is to be understood that stents are preferred for maintainingopen blood flow passageways in or through the myocardium. However, insome cases, stents may be omitted, for example, in the embodiments ofFIGS. 10C, 11, 12, 14A and 14B and 15, depending on the needs of thepatient.

[0164] Generally, stent 36 (FIG. 3), upstream portion 56 (FIGS. 6A, 6B)when in the form of a stent, stent 70 (FIG. 8), plugs 98, 98 a, 98 b(FIG. 11), stents 106 a-106 d (FIG. 12), and plugs 122, 122 a, 122 b(FIG. 15) have lengths which are predetermined by measuring thethickness of the myocardium. Procedures for such measurements aredescribed in U.S. Pat. Nos. 5,429,144 and 5,662,124, the disclosures ofwhich are hereby incorporated by reference in their entirety.

[0165] Self-Inserting Conduits

[0166] As is well known, the coronary artery CA branches off the aortaAO and is positioned along the external surface of the heart wall HW.Oxygenated blood flows from the heart PH to the aorta AO, into thecoronary artery CA, and on to the rest of the body. In some individuals,plaque builds up within the coronary artery CA, blocking the free flowof blood and causing complications ranging from mild angina to heartattack and death.

[0167] In view of restoring the flow of oxygenated blood through thecoronary artery CA, embodiments are disclosed which provide for theshunting of blood directly from the heart to a site in the coronaryartery CA which is distal to the blockage BL. In a similar manner tothat described above, a single rod-like conduit may utilize posteriorheart wall access in order to be inserted through the walls of thecoronary artery CA and the heart wall HW, and from there into the leftventricle LV of the heart PH which lies beneath the coronary artery CA.The hollow conduit is positioned such that the openings on either end ofthe conduit are within the coronary artery CA and the left ventricle LV.Blood flows through the opening in the left ventricle LV, through thehollow conduit and out of the opening positioned in the coronary arteryCA distal to the site of the blockage BL. Thus, the self-insertingconduit is preferably rigid or at least semi-rigid in order to providethe ability to pierce through the heart wall or other tissue of thepatient and to install the conduit as described above. In this case, theconduit is preferably a delivery rod in that it provides for its owndelivery.

[0168] Referring to FIG. 17, there is shown a cross-sectional view of atypical heart PH, aorta AO, and the coronary artery CA having a blockageBL therein. The coronary artery CA lies along the external surface ofthe wall of the heart HW. As is well known, the coronary artery CAsupplies oxygenated blood pumped from the left ventricle of the heart LVand through the aorta AO to the heart muscle or heart wall HW.

[0169]FIG. 17 also illustrates in schematic fashion a bypass device 210implanted distal to the blockage BL in the coronary artery CA. It shouldbe noted that only the presently preferred embodiments of the bypassdevices are described herein and only then in accordance with certainfigures. However, arteries and vessels other than the coronary artery CAmay be treated. As used herein, the term “vessel” shall be deemed toembrace any body organ, vessel, space or vasculature, includingartificial members or prior implants, which contains or can containbodily fluid. In addition, other types of blockages or vascular defectscan be treated, including, for example, vascular bypass in other areasto alleviate problems such as aneurysms, deep vein thrombosis, or othertypes of calcified or stenosed vessels. Embodiments described herein maybe used to bypass obstructed bile ducts in the liver, or to direct theblood supply away from tumors in an effort to destroy them. Accessdevices using configurations other than conduit devices as hereindescribed, may also be implemented. Thus, the following descriptionshould not be construed to be limiting in any way.

[0170] Referring to FIG. 18, there is shown in greater detail onepreferred embodiment of the bypass apparatus 210 of the presentinvention. The apparatus 210 is preferably formed of a biocompatiblematerial, such as metal or a polymer. The apparatus 210 is shownpiercing the coronary artery CA distal to the site of the blockage BL.The details of this conduit device 210 are described below. Inconnection with the somewhat schematic representation of FIG. 18, itwill be noted that the device 210 pierces completely through thecoronary artery CA, with the central portion 212 of the device 210positioned within the myocardium HW and the distal portion 214 of thedevice 210 implanted in the left ventricle of the heart LV.

[0171] Each shunt device 210 (FIG. 18) is comprised of a central portion212 formed by a hollow lumen having respective aperture or openings 216,218 on each end. One opening 216 receives blood from the left ventricleLV and shunts it through the lumen and out the other opening 218 whichis positioned in the coronary artery CA. The conduit 210 thereforeallows oxygenated blood to flow directly from the left ventricle LV andinto the coronary artery CA, as indicated by the arrows 219 a and 219 bin FIG. 18.

[0172] The distal end of the conduit 214 may be blunt (FIG. 20B) ortapered if desired (FIG. 18) to aid in the insertion of the device 210through the coronary artery CA, the heart wall HW and the left ventricleLV. The proximal end 220 of the conduit 210 is preferably provided witha head portion 222 that is larger than the diameter of the lumen (FIG.18), to help anchor the conduit 210 in place and prevent it frommigrating or passing completely through the coronary artery CA. Thishead portion 222 also acts to seal the puncture in the coronary arteryCA formed by the distal tip 214 of the conduit 210. The blood thereforeflows through the conduit 210 and downstream within the coronary arteryCA and not out through the puncture opening. If desired, the headportion 222 of the device 210 may be sutured into the surrounding tissueto prevent the device 210 from migrating from its proper position.Additional anchoring in the form of sutures or other means 224 is alsopreferably provided along the central portion 212 of the conduit 210.Anchoring the device 210 into the myocardium HW prevents migration ofthe conduit 210 from its proper position.

[0173] As illustrated in FIG. 18, the conduit 210 may also include asecond opening 225 at its proximal end 220 opposite from the firstopening 218. This second opening 225 allows for the perfusion of bloodfrom the coronary artery CA as shown by the arrow 221 in FIG. 18, i.e.,if the blockage BL does not completely block the coronary artery CA,blood may perfuse past the blockage BL and through the second opening225. FIG. 18A illustrates a self-inserting conduit having a flange orhead with dual prongs 227 to prevent rotation of the conduit in thecoronary, to ensure proper blood flow through the opening 218.

[0174] In installing the device of this embodiment, the surgeon may makea small incision of a keyhole type in order to gain access to theblocked vessel. Visual access may be obtained through thoroscopy orsimilar endoscopic procedure. Such access is very minimally invasive.Once the area of blockage is located (through fluoroscopy, etc.), theconduit 210 is implanted in the body in the manner described above. Theconduit device 210 is preferably introduced by way of an automatic gunor needle in order to reduce procedure time and avoid bleeding, but theconduit 210 may be implanted in other ways as well.

[0175] One method for implanting the device is illustrated in FIGS.19A-C. The conduit 230 is first mounted over a needle 232 (FIG. 19A),and the needle 232 is used to puncture the coronary artery CA, heartwall HW and left ventricle LV (FIG. 19B). The distal end of the needle232 is indicated by reference numeral 233. The needle 232 is thenremoved (FIG. 19C) and the anterior hole in the coronary artery CA isclosed using sutures 234 or other suitable methods.

[0176] In an alternate method illustrated in FIGS. 20A and 20B, a flapFL is first cut in the wall of the coronary artery CA and the needle 232bearing the conduit 230 is inserted through the flap FL and through theother side of the coronary artery CA, through the heart wall HW, andinto the left ventricle LV. The needle 232 is withdrawn, leaving theconduit 230 in place. The flap FL is then closed using sutures 234 orother suitable means.

[0177] The conduit 230 is preferably anchored in place in the heart wallHW as described above to prevent migration and to ensure that the freeflow of blood from the left ventricle LV to the coronary artery CA ismaintained.

[0178] Coronary Bypass

[0179] Referring to FIG. 21, there is shown a cross-sectional view of atypical heart anatomy including the aorta AO with a blockage BL orstenosis in the coronary artery CA which is positioned along theexternal surface of the heart wall HW. As is well known, the coronaryartery CA supplies blood pumped from the left ventricle LV to the aortaAO and into the heart muscles or myocardium HW.

[0180]FIG. 21 also illustrates in schematic fashion a bypass device 310mounted both proximally and distally of the blockage BL by means ofconduit combination access/shunt devices 312 and bypass conduit 314,described in more detail below.

[0181] Referring to FIG. 22, there is shown in greater detail onepreferred embodiment of the bypass apparatus 310. The apparatus 310 ispreferably formed of a biocompatible material, such as metal or apolymer. A pair of combination access/shunt devices 312 is shownproximally and distally of the blockage BL. The details of these conduitdevices 312 are described below and shown in connection with FIGS. 24and 25. In connection with FIG. 22, it will be noted that eachaccess/shunt device 312 pierces completely through the coronary arteryCA on the outside, leaving the conduit portion 316 of the device 312implanted in the wall of the heart wall HW. The conduit portion 316pierces not only through the coronary artery CA, but also into thetissue to provide anchoring and stabilization of the artery. The conduitportion 316 can be embedded in a tissue or passed completely through thetissue and into the left ventricle LV as shown in the portion of thedevice distal to the blockage BL.

[0182] FIGS. 22A-22B illustrate two alternative embodiments for conduitsof the nature described above. In FIG. 22A, the conduit is preferablyplaced proximally in the coronary artery CA to preferably allow some ofthe proximal flow in the coronary artery CA through the conduit and pastthe blockage BL to a downstream location in the coronary artery CA. Thisembodiment is preferably utilized in connection with blockages which arenot complete, and yet advantageously also allows for bypass flow asdescribed above. The conduit of FIG. 22B, however, does not allow anyproximal flow through the coronary and all flow is diverted through thebypass.

[0183] Each access/shunt device 312 (e.g., see also FIG. 24) iscomprised of a shunt portion 318 having an aperture 320 which, in thecase of the proximal device, receives blood from the coronary artery CAand shunts it into a diversion tube 322 mounted proximally with respectto the conduit portion 316 and the aperture 320. The diversion tube 322is in fluid communication with the aperture 320 to allow blood flow fromthe coronary artery CA into the aperture 320 and into the diversion tube322 as indicated by the arrows in FIG. 22. Mounted proximally withrespect to the diversion tube 322 is a connector piece 324 which is alsoin fluid communication therewith. The combination access/shunt device312 which is distal of the blockage BL may be constructed in a similarfashion or may have another configuration in which blood flows in thedirection opposite that indicated by the arrows in FIG. 22. The bypassconduit 314, which is hollow, is mounted on the two connector portions324 of the devices 312, as shown in FIG. 22, to allow blood to bypassthe blockage BL. The conduit 314 may be constructed from a vein orartery graft taken from the patient or a donor, an artificial veingraft, or any other biocompatible tubing including one made from a metalor polymer. All these connections are fluid-tight, as described below inmore detail, to avoid hemorrhaging. FIG. 22 illustrates the conduitportion 314 somewhat exploded away from the connector portions 324 inorder to illustrate the manner in which the complete bypass system canbe assembled.

[0184]FIG. 23 illustrates the conduit portion 314 of the bypass system310 completely press-fit or snapped-down over the connector portions 324(not shown in FIG. 23), as is the case in the final installation of thesystem.

[0185]FIG. 24 illustrates the combination access/shunt device 312 ingreater detail. The distal conduit portion 316, as described above,provides access to the coronary artery CA by piercing completely throughand into the surrounding tissue. A barbed distal portion 326 having oneor more barbs provides anchoring for the entire device. The proximalshunt portion 318 which resides in the vessel comprises the aperture 320to allow blood to flow therein and from there, at a right angle, intothe diversion tube 322 mounted proximally with respect to the aperture320, as indicated by the arrow in FIG. 24. The proximal shunt portion318 may be tapered if desired to aid in the insertion of the device 312through the coronary artery CA and into the heart wall HW. Mounted ontop of the-diversion tube 322 is a connector tube 324 for receiving thebypass conduit 314 as described above. It will be noted that theconnector tube 324 is frusto-conical in order to provide a fluid-tightpress-fit for the bypass.

[0186] In a preferred embodiment, a biocompatible fabric or mesh (notshown) is incorporated into the structure of the device. This fabric ormesh helps to seal the vessel to prevent bleeding and provides astructure which allows endothelial cells to infiltrate the device 312and incorporate it into the surrounding tissues.

[0187] Likewise, FIG. 24 illustrates an inverted U-shaped saddle portion328 of the device 312 which serves a dual purpose. This saddle portion328 fits over the artery when the combination access/shunt device 312 isinstalled therein, thereby stabilizing the artery. In addition, thissaddle device 328 acts as a flange for self-sealing the puncture in thecoronary artery CA formed by the barbed distal tip 326. In addition, thecollar or saddle that may help contain the artery and mitigate anypossible migration problems. Thus, blood flows through the diversiontube 322 and not out through the puncture opening. If desired, a loopmay be added to the saddle portion 328 to allow the device to be suturedinto the myocardium HW to prevent the device from migrating from itsproper position.

[0188]FIG. 25 is an alternative embodiment of the conduit access/shuntdevice of FIG. 24 in which a planar flange 330 serves to stabilize theartery and to self-seal the puncture therein.

[0189]FIGS. 27 and 28 show views of two additional embodiments fordevice 312. FIG. 27 shows device 312 having a tapered configuration toaid in the insertion of the device 312. FIG. 28 shows a device 331having dual distal tips to prevent rotation of the device when installedin the tissues of the patient.

[0190] In installing the device 310, the surgeon may make a smallincision of a keyhole type in order to gain access to the blockedvessel. Visual access may be obtained through thoracoscopy or similarendoscopic procedure. Such access is very minimally invasive. Once thearea of blockage is located (through fluoroscopy, etc.), one or both ofthe combination access/shunt devices 312 are installed in the artery inthe manner described above. The conduit devices 312 would preferably beintroduced by way of an automatic gun which would implant both conduitdevices 312 and the conduit 314 at the same time in order to reduceprocedure time and avoid bleeding. Alternatively, the conduits 312 couldbe introduced individually, provided that bleeding is controlled.

[0191] The device 310 can be sutured in place to provide for permanentbypass; alternatively, the device can be implanted temporarily tomaintain the flow of blood through the coronary artery CA during bypasssurgery. The device 310 is implanted as described above. A vein graft issutured in place, with one end anastomosed to the aorta, and the otherend to the coronary artery CA at a site distal to the blockage. Thedevice 310 provides blood flow from the aorta to the coronary artery CAat a site distal to the blockage BL during the anastomosis. Once bloodflow has been established through the vein graft, the bypass device maybe removed.

[0192]FIG. 29 illustrates a further embodiment of the combinationaccess/shunt device 312. The distal conduit portion 316, as describedabove, provides access to the coronary artery CA by piercing completelytherethrough and into the surrounding tissue. The barbed distal portion326 having one or more barbs provides anchoring for the entire device.The proximal shunt portion 318 which resides in the vessel comprises anaperture 320 to allow blood to flow therein and from there, at a rightangle, into the diversion tube 322 mounted proximally with respect tothe aperture 320. The proximal shunt portion 318 may be tapered ifdesired to aid in the insertion of the device 312 through the coronaryartery CA and into the heart wall HW. Mounted on top of the diversiontube 322 is a connector tube 324 for receiving a bypass conduit asdescribed above. It will be noted that the connector tube 324 can befrusto-conical in order to provide a fluid-tight press-fit for thebypass. In a preferred embodiment, a biocompatible fabric or mesh (notshown) is incorporated into the structure of the device. This fabric ormesh helps to seal the vessel to prevent bleeding and provides astructure that allows endothelial cells to infiltrate the device 312 andincorporate it into the surrounding tissues. A planar flange 330 servesto stabilize the artery and to self-seal the puncture therein.

[0193]FIG. 30 illustrates a further embodiment of the combinationaccess/shunt device 312. The distal conduit portion 316, as similar tothat described above with respect to other embodiments, and has a barbeddistal portion 326 having one or more barbs for anchoring the device.The proximal shunt portion 318 which resides in the vessel comprises anaperture 320 to allow blood to flow into the diversion tube 322. Theproximal shunt portion 318 may be tapered. The top of the diversion tube322 forms a tapered connector portion 324 for receiving a bypass conduitas described above. It will be noted that the connector portion 324 canbe frusto-conical. In a preferred embodiment, a biocompatible fabric ormesh (not shown) is incorporated into the structure of the device, asabove. A planar flange 330 serves to stabilize the artery and toself-seal the puncture therein. Attached to the planar flange anddistributed thereabout are one or more retaining members 323, which cancomprise detents at the end thereof for engaging the bypass conduit. Thedetents can be in the form of hooks, clasps, split rings, pads, or thelike in order to mechanically retain the bypass conduit onto theconnector portion 324 of the diversion tube 322.

[0194] Referring now to FIG. 31, the shunt device 312 of FIG. 29 isdepicted in cross-section, where like features are referred to by thesame reference numerals. The view depicts the device 312 inserted intoan artery, such as the coronary artery CA of a patient, and furtherdepicts a blockage BL therein. A bypass conduit, for example, a vein orartery graft 314, is secured to the connector tube 324 of the diversiontube 322 above the flange 330. Optionally, an access port or hole may beplaced along the shunt body opposite the aperture 320 at portion 332 toincrease total flow and to maintain blood perfusion through the vesselbypassed. It also should be noted that although the figure depicts thedevice 312 inserted perpendicular to the artery CA, the geometry of thedevice 312 allows it to be inserted at an angle without affecting itsperformance. This feature advantageously allows for more flexibleapplication of the device during surgery, where perpendicular access toa vessel is not always available or convenient. FIG. 32 presents a viewsimilar to that of FIG. 31, showing the barb 326 of the conduit deviceimplanted in the myocardium HW of a patient for perfusing the coronaryartery CA.

[0195] A side-by-side bypass device 412 is depicted in FIG. 33, and FIG.33A illustrates in schematic fashion the bypass achieved with theconduit of FIG. 33. In this case, the bypass conduit runs more parallelto the coronary artery CA and therefore utilizes less space within theintrapericardial space. In this device, the distal conduit portion 416is similar to that described above with respect to other embodiments,and has a barbed distal portion 426 having one or more barbs foranchoring the device. The proximal shunt portion 418 which resides in avessel comprises an aperture 420 to allow blood to flow into thediversion tube 422. The aperture 420 passes through the shunt portion418, and allows communication with the diversion tube to either side ofthe shunt portion 418. The proximal shunt portion 418 may be tapered.The top of the diversion tube 422 forms a connector portion with asecond aperture 421 for communicating with a bypass conduit, such as anartery or vein graft. As above, a biocompatible fabric or mesh (notshown) can be incorporated into the structure of the device. A planarflange 430 serves to stabilize the artery and to self-seal the puncturetherein. Similarly, a flange 434 is provided at the end of the diversiontube 422 to self-seal the puncture in the artery or vein graft.

[0196]FIG. 34 depicts an alternative embodiment 412′ similar to thedevice of FIG. 33. The device of FIG. 34 has an aperture 420′, whichextends through only one side of the shunt portion 418′. It should beunderstood that the apertures of this and the preceding embodiment maybe selectively placed and sized according to the desired application,the orientation of the blood vessels employed, and the location ofanatomical features, blockages, etc.

[0197]FIG. 35 depicts a further alternative embodiment 412″ that issimilar to the embodiment depicted in FIGS. 33 and 34 except that thereis no flange between the apertures 420 and 421, but rather a smoothtransition area 430″. The shunt body 418″ is shown to have a gentletaper.

[0198]FIG. 37 is a cutaway schematic representation of the shunt device412′ depicted in FIG. 34 mounted within the patient, with the conduitend resident within the myocardium HW. The coronary artery CA and thebypass graft 414 are shown to be placed in fluid communication by theapertures 420′, 421 in the shunt 412′. This illustration is illustrativeof all side-by-side instant anastomosis devices described herein.Further, it should be noted that a hole may be located at position 436to allow additional perfusion of the coronary artery CA, and that theaperture 420′ could pass through both sides, as in devices 412 and 412″.Further, it should be noted that the device could be mounted at anangle, as discussed hereinabove.

[0199]FIG. 38 is a cutaway schematic representation of a “rivet” typeshunt device 512 mounted within the patient, with the retention members540 deployed. A flange 534 seals the incision and maintains a bearingsurface against the bypass graft 514, which could be venous or arterial.An aperture 520 opens a channel into the hollow stent body 518, whichterminates in an open end 542. In this illustrative arrangement, theopen end 542 is resident within the coronary artery CA.

[0200] For illustrative purposes, it has been found that an anastomosisshunt device of the type depicted in FIG. 29 can be dimensioned to havea height of 12.5 mm, with a body width of about 2 mm, a flange diameterof about 2.8 mm, and an inside diameter of the diversion tube of about1.4 mm. The conduit can be dimensioned to be about 3 mm in heighttapering to a width of about 2.1 mm. The aperture can be dimensioned tobe about 1.4 mm in diameter, and can have an edge radius about theperiphery of about 0.10 mm all around. An anastomosis shunt device ofthe type depicted in FIG. 33 can be dimensioned to have a height of12.65 mm, with a body width of about 2.8 mm, a flange diameter of about3.4 mm, and an inside diameter of the diversion tube of about 2.0 mm.The conduit can be dimensioned to be about 3 mm in height tapering to awidth of about 2.6 mm. The apertures can be dimensioned to be about 2.0mm in diameter, and can have an edge radius about the periphery of about0.10 mm all around.

[0201] Anastomosis Devices and Methods

[0202] It will be noted in connection with the coronary bypass devices,systems, and methods described above that various connections from oneconduit to another are necessary. The term “anastomosis” refers to thejoining of two conduits or two vessels in a similar fashion; although,in the context of the present application, that term should not belimited to a particular medical definition or practice, but refersbroadly to the connection of various conduits in connection with bypasssystems. Thus, as described above, prefit connections from one conduitonto a hub of another conduit are possible, although other anastomosisconfigurations are described below.

[0203] As shown in FIGS. 39A and 39B, a conduit 600 can be used toprovide temporary blood flow during therapeutic procedures. For example,in typical coronary artery bypass surgery, a section of vein VG takenfrom the leg of the patient is attached at one end to the aorta AO andat the other end to a point distal to the blockage in the coronaryartery CA. This surgery requires the delicate procedure of joining thevein graft VG to the aorta AO and to the coronary artery CA. Thisjoining of the blood vessels is known as anastomosis. Normally, thepatient is placed on a heart-lung machine to keep the blood oxygenatedand flowing during this procedure, and the blood is diverted from thecoronary artery CA to allow the physician to complete the anastomosis.

[0204] In one embodiment of the present invention, the conduit 600 isused to maintain blood flow through the coronary artery CA during bypasssurgery (FIG. 39A). The vein graft VG is loaded on top of the stent 600prior to implantation. The conduit 600 is implanted as described above,at the point of the vein graft VG anastomosis. The vein graft VG issutured to the aorta and to the CA at a point distal to the blockage BL.If desired, the sutures can be preloaded onto the graft VG to facilitatethe anastomosis. Once the vein graft VG has been attached, the conduit600 is removed, and blood flow occurs from the aorta AO, through thevein graft VG, and down the coronary artery CA. The conduit 600 can besutured in place during the anastomosis procedure for permanentattachment, if desired.

[0205] Other embodiments for connecting vessels or segments of vesselstogether are shown in FIGS. 40-40G. FIG. 40 illustrates two vessels 1200and 1202 to be connected to respective disc members 1210 and 1212. Eachof the disc members 1210 and 1212 includes a plurality of prongs 1220which are configured to mate with opposing holes 1224. After the discmembers 1210, 1212 are secured to the vessels 1200 and 1202 (FIG. 40A),the vessels 1200 and 1202 may be effectively joined by snapping orlocking the disc members together. As illustrated in FIG. 40B, this maybe done by aligning the prongs 1220 with the holes 1224, so that theprongs pass through and are accepted by the holes.

[0206] A technique for securing the vessels 1200 and 1202 to the discmembers is illustrated in FIGS. 40C-40G. FIG. 40C shows the vessel 1200(e.g., a left internal mammary artery or “LIMA”) being brought intoproximity with a disc member 1226, which, as shown in FIG. 40D, isbrought over the vessel 1200, so that a portion 1230 of the vessel 1200extends beyond the disc member 1226. As shown in FIG. 40E, the portion1230 may then be advantageously everted over the disc member 1226, sothat the prongs 1220 of the disc member 1226 pierce through the vesselportion 1230. As illustrated in FIGS. 40F and 40G, the disc member 1226may then be mated with another disc member 1234 having a plurality ofholes 1224 therein. The disc member 1234 may advantageously be part of alarger integrally formed conduit device 1240 for redirecting the flow ofblood around a blockage BL (not shown in FIG. 40F) within the coronaryartery CA. A spike 1250 may be used to secure the conduit device 1240within the heart wall HW. Although the disc member 1226 is shown ashaving several prongs 1220 that mate with respective holes 1224 inanother disc member 1234, it will be understood that disc members havingalternate holes and prongs (like those in FIGS. 40-40B) may be used.

[0207] Another conduit device 1254 is shown in FIG. 40H, in which thedevice 1254 includes a disc member 1234 that mates with another discmember 1226. The conduit device 1254 is held snugly within the coronaryartery CA by a rim element 1258 of the device 1254. In FIG. 40I aconduit device 1260 is shown that includes a spike 1262 for securing thedevice 1260 into the heart wall HW. A vessel 1200 fits around acylindrical portion 1264 of the conduit device 1260 and is held aroundthe cylindrical portion 1264 by friction or with a ligature 1268.

[0208]FIG. 40J shows a conduit member 1280 having a pair of rings 1282and 1284. As shown in FIG. 40K, one of the rings 1282 fits snugly insideand against the wall of the coronary artery CA, while the other ring1284 sits above and on top of the coronary artery CA. A vessel 1200 fitsover the ring 1284 and may be held in place with a suture 1286.

[0209]FIG. 40L shows another conduit member 1290, a base 1292 of whichrests on the coronary artery CA, as illustrated in FIG. 40M. A suture1286 may be used to secure the vessel 1200 to a ring 1294 of the conduitmember 1290.

[0210]FIG. 40N shows another conduit member 1300 which functions similarto its counterpart in FIG. 40L, except that instead of a ring 1294, aplurality of teeth 1304 are used for holding the conduit member 1300 inplace. Specifically, a vessel is brought over the conduit member so thatthe vessel slides beyond the teeth 1304. As the vessel 1200 is thenretracted, the teeth 1304 engage the vessel 1200, thereby securing thevessel 1200 to the conduit member 1300, as shown in FIGURE O.

[0211] Another conduit member 1320 is shown in FIGURE P. The member 1320includes a ring 1324 and a plurality of teeth 1328. When in use, thering 1324 contacts the inside of the coronary artery CA, whereas theteeth 1328 engage the vessel 1200 in a manner analogous to theembodiment of FIGS. 40N-O.

[0212] Conduits With Flow Resistance

[0213] One of the advantages of certain embodiments of the presentconduits is that they can be designed to optimize fluid or blood flowthrough them. That is, the design or configuration of a conduit may besuch that it automatically achieves flow control without microvalves,check valves, or other moving devices. (See, for example, the conduitsof FIGS. 6A-H and 8-8P.) Such moving or articulating devices may becomplicated or expensive to manufacture, particularly on the smallscales required in this context. Thus, in one embodiment, flow controlis achieved by maximizing flow through the conduit in one direction(preferably from the left ventricle to the coronary artery), butminimizing flow through the conduit in the opposite direction. Sinceflow rate through the conduit is a function of friction or drag,turbulence, and other fluid dynamic parameters, it may be convenient todiscuss flow rate through the conduit in terms of resistance of theconduit to such flow. In other words, in one embodiment, it isadvantageous to have a low conduit resistance in the forward direction(from the left ventricle to the coronary artery), but a higherresistance in the opposite direction. In that sense, the conduit acts asa type of choke device having a higher reversed flow resistance ordiastolic resistance than the forward flow or systolic resistance.

[0214] Experimentation has shown, however, that the abovecharacteristics may not necessarily produce optimized flow rate in thecoronary artery. Thus, it should be remembered that flow rate throughthe conduit should be controlled such that it enhances total coronaryflow rate, which total coronary flow rate is essential for perfusion ofthe heart tissues. Thus, experimentation has shown that the degree ofproximal occlusion may have an effect on total coronary flow rate. Ithas been determined that, where a proximal occlusion is only partial,the total flow rate in the distal coronary artery may increase withgreater systolic resistance in the conduit. This may be due, at least inpart, to the back pressure which the flow through the conduit sees as aresult of the partial occlusion. Thus, optimization under thesecircumstances must take into consideration the degree of proximalocclusion. In this regard, it has been determined that total coronaryflow rate is increased with increasing systolic resistance through theconduit. Preferably, diastolic resistance remains high. For example, ithas been found that with mild systolic resistance, an increase incoronary flow rate was achieved with approximately zero negativediastolic flow.

[0215] Thus, referring to FIG. 41, there is shown in schematic,cross-sectional view a conduit 1400 which has been designed to achieveflow optimization under certain circumstances, and which acts as anasymmetrical flow resistor. In this case, the conduit 1400 is generallycurved with varying wall thickness, and has a proximal end 1404 whichextends into the left ventricle LV and a distal end 1408 which curves sothat its exit is approximately transverse to the direction of flow inthe distal portion of the coronary artery CA. In this context, the term“distal” is used with respect to direction of flow and represents alocation downstream from a given point in the flow path. It will beobserved that the proximal portion of the conduit 1400 shown in FIG. 41extends into the left ventricle LV to take into consideration thechanging wall thickness of the myocardium. Thus, the proximal portion ofthe conduit 1400 may extend into the ventricle LV roughly 5%-30% toaccommodate for such changing wall thicknesses. Thus, during systole,the myocardium HW contracts and goes into tension, thus increasing thethickness of the myocardium. The conduit 1400 of FIG. 41 is designed toaccommodate such a thickening such that its entrance 1412 will beapproximately flush with the internal surface of the myocardium HWduring systole.

[0216] It will also be observed at the proximal end 1404 of the conduit1400 that the entrance 1412 is shaped so as to have a high radius ofcurvature, which is approximately ½ of the difference between thediameter at the exit 1416 and the diameter of the conduit 1400 at theentrance 1412. This curvature tends to reduce flow losses (or in otherwords, decreases resistance to flow) at the entrance 1412, therebymaximizing flow through the conduit during systole. At the same time, itwill be observed that the decreased diameter at the entrance 1412increases the resistance to reverse diastolic flow at that location,thus tending to decrease negative flow through the conduit 1400 or flowfrom the coronary artery CA back into the ventricle LV. Thus, theproximal portion of the conduit 1400 is designed so as to achieve anabrupt expansion resulting in large exit losses and consequently highresistance to diastolic flow.

[0217] At the distal end 1408, on the other hand, flow losses areminimized, so as to minimize flow resistance. Such exit losses areessentially zero because the exit diameter of the conduit 1400proximates or matches the diameter of the coronary artery CA. Moreover,during diastolic flow, there will be an “entrance” losses at the exit ofthe conduit 1400, thus increasing the resistance to such negative flow.Moreover, the curved configuration of the distal end 1408 of the conduit1400 minimizes flow loss during diastole which results from proximalflow through a partial occlusion. In other words, the distal end 1408 ofthe conduit 1400 can be constructed so as to allow a proximal flowpassing a partial occlusion and contributing to the flow through theconduit 1400 to produce an advantageous total coronary flow rate. Suchdistal designs for the conduit 1400 are described elsewhere herein andare compatible with the conduit of FIG. 41. Moreover, the conduit 1400can be constructed from a rigid or flexible material, it may be a solidwall or lattice structure (e.g., stent-like) as described below.

[0218] Thus, the conduit 1400 of FIG. 41 can be designed so as tooptimize total flow rate by designing a certain flow resistance throughthe conduit 1400 in accordance with the conditions indicated by thepatient. In this embodiment, the wall thickness of the conduit 1400varies by a taper (θ) of approximately 4°, thus producing thedifferences in entrance and exit diameters. This degree of taper tendsto minimize losses in a gradual conical expansion region.

[0219] Referring to FIGS. 42-45, it can be seen that other conduitconfigurations can result in advantageous flow resistance. These conduitdesigns may or may not embody the design characteristics of the conduit1400 of FIG. 41. For example, shown in FIG. 42 is a schematic view of acurved conduit 1430, similar to that of FIG. 41, except having a spiralflow path 1434 therethrough. This spiral flow path 1434 increases theresistance to negative or diastolic flow. By the same token, duringsystole, the pressures available are sufficient to overcome theresistance presented by the spiral flow path 1434. In this case, theconduit 1430 may be of solid configuration and having a spiral flow pathcut or bored therethrough. On the other hand, the conduit 1430 may bemanufactured in a spiral fashion comprising a hollow flow path throughthe spiral.

[0220] Similarly, as shown in FIG. 43, there is shown a conduit 1440with a helical flow path 1444. Again, this conduit 1440 takes advantageof the increased flow resistance in the negative or reverse flowdirection during diastole. The side walls of these conduits may bestraight or tapered, as shown in FIG. 41, to further effect the degreeof resistance. Thus, not only does the blood flow see a larger pressuredifferential between the vessel and the ventricle, but it may also seean increasing pressure due to a gradually tapered, smaller diameterblood flow path in the reverse direction. Again, however, this designmay be reversed (in order to increase forward resistance) where only apartial occlusion is presented.

[0221] FIGS. 44A-44C utilize an alternate method of flow resistancewhich comprises a type of fluidic vortex diode. Referring to FIG. 44A,there is shown a conduit 1450 having an entrance 1454 and an exit 1458.It will be appreciated that the entrance 1454 and exit 1458 can bepositioned in the ventricle LV and coronary artery CA, respectively, andthat this illustration is only schematic with respect to the placementof the conduit 1450 in the heart tissues of the patient. Furthermore, asdiscussed above, the entrance 1454 and exit 1458 may be placed in theventricle LV and coronary artery CA, respectively, or vice versa,depending upon patient indications and the desired flow optimization.Thus, it is convenient with respect to FIGS. 44A and 44B to discuss themin terms of a high resistance direction (shown in FIG. 44A) and a lowresistance direction (shown in FIG. 44B). Both such flow resistances areachieved in a single device by providing a chamber or housing(preferably circular) with a tangential flow port and a central axialflow port. If the direction of flow is such that fluid enters thetangential flow port and exits the axial flow port, as shown in FIG.44A, a vortex 1462 is created in the circular chamber. This vortex 1462greatly impedes the flow of fluid through the device and provides for ahigh resistance fluid flow conduit. The fluid dynamics behind thisresult are such that the rotation of the fluid in the chamber generatescentrifugal forces that cause the fluid to push outward toward theperiphery of the chamber. Since fluid is entering the chamber at theperiphery where the resulting centrifugal forces react, the outward pushof the rotating fluid impedes the flow.

[0222] When the flow direction is reversed, such as that shown in FIG.44B, fluid flows into the chamber 1468 from the central axial flow port1472 and from there to the tangential flow port 1476. However, no vortexis created. Thus, the resistance of conduit 1450 to the flow of fluid inthis direction is relatively low.

[0223] A conduit 1480 utilizing this type of vortex diode device isshown in FIG. 44C. Thus, in this embodiment, the tangential flow port1484 is placed in the coronary artery CA such that a high resistance toreverse flow is generated. On the other hand, the entrance 1486 to theaxial flow port is placed in the ventricle LV so that blood flow intothe conduit 1480 sees low resistance.

[0224]FIG. 45 illustrates an alternate embodiment of a conduit 1490utilizing flow resistance. In this case, the conduit 1490 is in thenature of a tesla valvular conduit. The geometry of the flow path inthis device is such that flow entering the conduit 1490 from onedirection 1494, which is generally likely to occur during diastole, isbifurcated at several locations with part of the flow being conductedinto passages 1496, 1498 that redirect portions of the flow back intothe main flow stream 1494 in a direction 1500 that is essentiallyreversed to the direction 1494 of the main flow stream. This reverseddirection 1500 flow impedes the main flow stream 1494 and sets up a highresistance to fluid flow. On the other hand, when fluid enters in theopposite direction 1502, such as is likely to occur during systole, nosuch bifurcation and no resulting flow impedance occurs. Thus, as shownin FIG. 45, the higher resistance flow direction is from the coronaryartery CA toward the ventricle LV. Flow in that direction 1494experiences at least two bifurcations 1496 a, 1498 a with resultingreverse flow 1500 to impede diastolic blood flow. On the other hand,flow 1502 from the ventricle LV toward the coronary CA does notexperience any bifurcations, thus resulting in lower flow resistance.

[0225] Conduits With Proximal Extensions

[0226] As discussed above, flow resistance in the direction of ventricleLV to coronary artery CA can be reduced by an increased exit diameter atthe conduit distal portion which opens into the coronary artery CA. Atthis location, a conduit exit diameter which approximates or matches thediameter of the coronary will result in decreased flow losses andminimize flow resistance. Due to the curvature of the conduit, the flowat the conduit exit is approximately parallel to the axial flow in thecoronary. Thus, this distal conduit portion may serve not only as anadvantageous controller of the flow, but the extension nature of thedistal portion can also serve to anchor or support the conduit in itsposition. Furthermore, as noted above, this distal portion of theconduit can be designed to allow proximal flow past a partial occlusion,past the distal portion of the conduit, and into the lower coronaryregions for profusion of the heart.

[0227] Thus, referring to FIG. 46, there is shown a schematic, partialcross-sectional view of a curved conduit 1600 having an extensionportion 1604 at its proximal end (to take into consideration changes inmyocardial thickness) and a distal extension 1608 at the conduit distalend extending into the coronary artery CA. Besides minimizing flowlosses and anchoring the conduit 1600 in place, this distal extension1608 also reduces trauma to the coronary artery CA by directing flowdownstream in a substantially parallel direction.

[0228] The conduit 1600 of FIG. 46 may be installed in one embodiment,in accordance with FIGS. 47A-D. Thus, with reference to FIG. 47A, thecurved tubular conduit 1600 may have a sharpened or pointed proximal tip1612 to allow it to penetrate the heart tissues, including at least thecoronary artery CA and the myocardium HW so that the proximal endextends into the ventricle LV, as shown in FIG. 47B. The curved conduit1600 is advanced in a rotational or curved fashion, as shown in FIG.47C, so that it extends well into the ventricle LV. In fact, the conduit1600 can be of such a length and constructed from a material to allow itto bend and curve into the coronary artery CA in a downstream fashion,as shown in FIG. 47C. Thus, the curved conduit 1600 actually is placedso as to bypass its final destination to allow it to be curved and theninserted in a downstream fashion as shown in FIG. 47D.

[0229] An alternate embodiment of the conduit 1600 of FIG. 46 is shownin FIG. 48. In this case, the hollow, curved, tubular conduit 1630 isprovided with an atraumatic ball configuration 1634 at the distal end ofthe conduit 1630. This configuration allows for reduced flow losses atthe exit, while at the same time providing a proximal extension whichsecures the conduit 1630 in place without damaging the sensitive liningsof the vessel. Alternatively, the neck of the conduit 1630 just proximalthe end having the atraumatic ball 1634 provides a location for ananchoring suture or tether 1638, as shown in FIG. 48. The proximal endof the conduit 1630 can be provided with a non-coring, deflective point1642, and the tubular section 1646 can be constructed from a surgeon'sneedle having a {fraction (3/8)} inch radius of curvature. As with allthe conduits depicted herein, they can be installed in a variety ofvascular or surgical procedures, depending upon patient indications.Thus, the conduit 1630 of FIG. 48 may be implanted in the mannerillustrated in FIGS. 47A-47D. Alternatively, it may be inserted by meansof a curved trocar or stylet, or may even travel over a thin guidewire.The conduit 1630 may be constructed from a rigid or semi-rigid material,it may have solid walls or a lattice stent-like construction asdiscussed below.

[0230]FIG. 48A illustrates the conduit 1630 of FIG. 48 in itsuninstalled condition. FIGS. 48B-C illustrate alternate embodiments inwhich the atraumatic ball end at the distal end of the conduit 1630 isreplaced with a partial ball 1650 or semi-spherical section, shown inFIG. 48B, or a flange-type structure 1654 as shown in FIG. 48C.

[0231] Another embodiment of a conduit 1670 having a proximal extensionis shown in FIG. 49. In this case, the proximal portion 1674 of theconduit 1670 and the main body 1678 portion thereof which extends to themyocardium HW are relatively stiff or rigid regions. These portions ofthe conduit 1670 can be constructed from a smooth material, such as ametallic stainless steel or nitinol hypotube. Thus, a laminar flowpattern is generated in the conduit 1670 in these regions.

[0232] On the other hand, as the flow approaches the artery CA, theconduit 1670 can be constructed from a combination of laser cut hypotubeand elastomer to provide a flexible distal portion which extendsproximally into the coronary artery CA. In the embodiment of FIG. 49,the curved section of the conduit 1670 is stent-like or is of a latticeconstruction. It can be manufactured by laser cutting of a nitinolhypotube with elastomeric sections joining the lattice portions. Theproximal extension 1674 may comprise at least a unitary arm with acircular flow exit 1682, as illustrated in FIG. 49.

[0233] Alternatively, as shown in FIGS. 50A-50C, the conduit of FIG. 49can be constructed so that it is substantially entirely of a latticeconstruction or stent-like. In this case, the term stent-like is used torefer to coronary stents which are often implanted followingangioplasty, and is thus in an illustrated manner only and not to berestrictive in any sense of the term. Thus, as shown in FIG. 50A, thereis a conduit 1690 having a solid or smooth proximal end 1694 whichextends into the ventricle LV and a main body section 1698 which is of alattice-type construction. This section likewise can be constructed fromthe laser cutting or other cutting of a nitinol hypotube or othermaterial. FIG. 50B illustrates the conduit 1690 of FIG. 50A prior tohaving its distal portion 1702 bent so as to extend into the distalregions of the coronary artery CA. FIG. 50C, on the other hand,illustrates the conduit 1690 of FIG. 50A as installed in the hearttissues with the distal portion 1702 curved so as to align with thecoronary artery CA.

[0234] The lattice construction of the conduit 1690 of FIGS. 50A-C maybe constructed from a variety of materials. FIGS. 51A-51D illustratevarious constructions for the conduit 1690 in FIG. 50. which includes asingle arm with an opening at its end. In each case, the conduit 1690 iscomprised essentially of a tapered or pointed proximal section 1694which extends into the ventricle LV, a main body 1698 of a latticeconstruction, and an extension arm 1706 and distal anchor 1710 whichextends into the coronary artery CA. The distal extension arm 1706 andexit portion can take on a variety of shapes as shown in FIGS. 51A-51D.These conduits 1690 can be constructed, preferably, from a nitinoltubing of approximately 0.060 inches in outer diameter with an innerdiameter of approximately 0.048 inches. Another advantage of theseconduits 1690 is their flexibility in the main body region 1698 inresponse to changes in myocardial thickness. Also, due to the latticeconstruction at the distal end, proximal flow through the coronary CA isnot impeded.

[0235]FIG. 52 illustrates an alternate embodiment 1716 with a distalextension 1720 extending both distally in the coronary artery CA as wellas proximally. Thus, the distal portion 1720 of the conduit 1716 has aT-like configuration. As shown in FIG. 52, this T-like distal portion1720 of the conduit 1716 may have a lattice construction such as theconduit 1690 shown in FIGS. 50 and 51. The main body 1724 of the conduit171-6 of FIG. 52 may be a smooth tubular structure, or may be of alattice construction as shown in FIGS. 50 and 51.

[0236] The conduit 1730 of FIG. 53 has an articulating distal portion1734 which may fold down either in a manner so as to either extenddistally with respect to the coronary artery CA or proximally, as shownin FIG. 53. In this case, the distal extension 1734 of the conduit 1730is preferably of a lattice construction made from a nitinol hypotube asdiscussed above. This distal portion 1734 is designed to collapseagainst the main body 1738 of the conduit 1730 for insertion and thenextend to an approximately 90° position, as shown in FIG. 53, within thecoronary lumen after insertion. Thus, the distal portion 1734 of theconduit 1730 serves as an articulating or anchor arm for positioning thedevice within the heart tissues.

[0237]FIG. 54 illustrates an alternate embodiment 1750 having anelastomeric distal anchoring arm 1754 for the conduit 1750. In thiscase, the distal portion of the conduit 1750 is provided with a sealingportion 1758 and a shoulder portion 1762. Both of these may preferablybe constructed from elastomeric material or some other soft material.The sealing portion 1758 extends through a hole in the coronary arteryCA which is used to implant the conduit 1750 of FIG. 54. The shoulderportion 1762 supports the sealing portion 1758 and seals the openingagainst the coronary wall. The distal portion of the conduit 1750 itselfmay be constructed from a metallic or other flexible material such thatthe bias or bending characteristic of the conduit 1750 causes it to pushslightly at the distal end against the coronary wall, thus providing theseal.

[0238] The bypass devices and methods herein provide significantimprovements in the treatment of vascular blockages. It should beunderstood that while various anatomical features have been discussedherein for ease of reference, the anastomosis devices described hereincan also be used in connection with vessels other than coronary artery,etc. Thus, it is intended that the present invention is applicable to awide range of uses where vascular anastomosis is indicated. It isfurther intended that the present invention may applicable during a widevariety of surgical techniques, from conventional sternotomy or “openchest” procedures, to minimally-invasive direct coronary artery bypass(MDCAB) and even vascular approaches.

[0239] Accordingly, it is to be understood that the drawings anddescriptions herein are proffered by way of example to facilitatecomprehension of the invention and should not be construed to limit thescope thereof.

What is claimed is:
 1. An implantable body fluid shunt device forproviding fluid communication between body vessels of a patient, saiddevice comprising: a generally elongated shunt body having proximal anddistal ends, said shunt body being formed of a rigid, biocompatiblematerial; said shunt body having: a first proximal aperture and at leastone second aperture longitudinally spaced along said shunt body fromsaid first aperture; and a diversion tube having a predetermined shapeproviding fluid communication between said first aperture and said atleast one second aperture; wherein, in use, said device is implanted ina patient such that said first aperture is disposed within a firstvessel, and said at least one second aperture is disposed in a secondvessel.
 2. The implantable shunt device of claim 1, wherein said shuntbody further comprises a spike portion at a distal end thereof.
 3. Theimplantable shunt device of claim 1, wherein said shunt body furthercomprises expansible retention members at a distal end thereof.
 4. Theimplantable shunt device of claim 1, wherein said device providestransmyocardial blood perfusion, and wherein said second aperture isadjacent said distal end of said shunt body and in use is disposedwithin the left ventricle of a patient.
 5. The implantable shunt deviceof claim 4, wherein the first aperture is adjacent said proximal end ofsaid shunt body and in use is disposed within a coronary artery of apatient.
 6. The implantable shunt device of claim 2, wherein the secondaperture in use is situated within the coronary artery of a patient andwherein said spike portion is disposed within the myocardium.
 7. Theimplantable shunt device of claim 6, wherein the first aperture isadjacent said proximal end of said shunt body, wherein said firstaperture is disposed within a venous or arterial graft.